HP-8569 Spectrum Analyzer Repairs

[AF6LJ]

Finally it's time to start this project.
A friend acquired not one but three HP-8569B, and one HP-8569A spectrum analyzers.
One 8569B would not power up, that was an easy find a bad tantalum cap on the supply module's -15V rail. The power supply module was borrowed from one of the A model and all four analyzers appear at this point to have no electrical issues, however..........
All of them do have one or more of the rotary switches, damaged.

The front panels were removed from the two that are most likely to be easily fixed.
 
And a rear view...

Oh and then there are these...

The one on the left has been straightened and is ready for re installation.

Since the freely available manuals online were garbage, to put it nicely, I want to Artek Manuals http://artekmanuals.com/ and picked up the three volume set for a very reasonable price (under $20.00USD) and received a wonderfully scanned manual set.
These guys are great and the price is so reasonable....

Moving along to the immediate problem...

The switch rotor is a piece of what feels like ether nylon or delrin plastic. They have hot stakes that secure the contact fingers to the rotor, pay close attention to the inner pair of hot stakes, they were never used in this switch rotor, the outer ones as can be seen are sheered off, no doubt from the decades of pressure on the hot stakes....

At this point laziness kicks in, and I am going to ask if anybody has ever repaired these switch rotors before and what did you use to attach the contact fingers?

[SeanB]

Small PCB drill and a tiny nail, with the drill diameter being a little smaller than the nail diameter. The nail is a push fit into the hole, after cutting it to size, filing the head round and the shank to round, and to leave a small chamfer to the leading edge to allow easy entry into the hole.  Leave some ridges on the rivet shank, round the diameter, so it is harder to pull out.

You cannot use any glue or such, unless you know for sure it will not attack the plastic material, and if it is nylon in any case many do not work nicely with it. Some cyanacuralates might be compatible with nylon and delrin, but YMMV with it.

Done many a repair with rivets, including making new pins recently for my glasses to replace a stripped screw, and to replace worn pins in my watch strap. Of course also helps having used so many solid rivets in repairing airframe parts, and getting to know how to form them in places where it was impossible to get to them with a power riveter, but a small ball peen hammer was a perfect fit, plus i made a few mandrels to get the head shaped.

[AF6LJ]

I have some ideas, there are adhesives made for Delrin and Nylon.
It feels like Delrin and MEK (yes I still have some) will not attack the plastic, which confirms that this is not one of the more reactive plastics.

[SeanB]

If you are wanting MEK simply look for Linx solvent or a generic clone, which is MEK in a bottle. Used in continuous jet industrial printers, and a consumable there.

Still the rivet idea will work better than heat stakes, simply because it is a lot more area to hold them.

[AF6LJ]

If you are wanting MEK simply look for Linx solvent or a generic clone, which is MEK in a bottle. Used in continuous jet industrial printers, and a consumable there.

Still the rivet idea will work better than heat stakes, simply because it is a lot more area to hold them.

I have all the MEK I need.

I am thinking I am going to end up using glue...
I don't have a drill press and it's going to take a #60 or smaller drill.
I have a lot of these to fix.

[xrunner]

Don't have any better ideas on the switch, but I'll be following this thread with interest. 

[AF6LJ]

Don't have any better ideas on the switch, but I'll be following this thread with interest. 

Good I am thinking the glue is the way to go.
I just have to find something that sticks.

[AF6LJ]

I do plan on exploring the possiability of using both glue and a small screw to anchor the contact fingers in place.
Anybody know where I can get more of those fingers?

[donmr]

Does the slot for the fingers extend to where the inner pair of stakes is?

When I worked for HP some time ago, they made products to be repaired.  They might have made contact fingers with a longer tail on them for attachment with the inner stakes.  Of course you would have to get or make some like that to use them.

[AF6LJ]

Does the slot for the fingers extend to where the inner pair of stakes is?

When I worked for HP some time ago, they made products to be repaired.  They might have made contact fingers with a longer tail on them for attachment with the inner stakes.  Of course you would have to get or make some like that to use them.

I haven't been able to find any.

The switch set up is like I have seen in some HP scopes, the same type of rotatory switch configuration.  Still looking while I wait to get the items to fix what I have. 

[mmagin]

I do plan on exploring the possiability of using both glue and a small screw to anchor the contact fingers in place.
Anybody know where I can get more of those fingers?

Some of the high temperature hot-melt adhesives are amazing (and will stick to a lot of things), though you have to be careful when applying them to plastics with lower melting points (polyethylene, polypropylene, etc).  Nylon may be okay, I dunno.

[cncjerry]

two options:

1) Put the fingers on the posts and melt them around it with a soldering iron.  Find some of the excess material and use it as filler mixing it around with heat.

2)  Send the delrin/nylon material parts to me and I will drill them for you for the cost of return postage.  Then use two small screws to hold them down.

[AF6LJ]

two options:

1) Put the fingers on the posts and melt them around it with a soldering iron.  Find some of the excess material and use it as filler mixing it around with heat.

2)  Send the delrin/nylon material parts to me and I will drill them for you for the cost of return postage.  Then use two small screws to hold them down.

I am going to give option two serious consideration.

[AF6LJ]

Today I did a test drill in the one rotor I had already removed, I think I am going to drill, tap and install 0-80 retaining screws on the switch contacts that I can, a dab of Epoxy will secure the screw head to the edge of the contact base...
This should work...
Here is one of the good ones I pulled from the same module I am working over..

These contacts are working loose as can bee seen below.



For those who may not be sure how these switches work the contacts slide across the plated tracks on the circuit board. On the left as seen above is the resolution bandwidth stationary contacts, the broken rotor and contact assembly came from that switch.
The switch on the right is the sweep selector switch contacts. The wide contact in the center is the ground contact.

[xrunner]

Looks good so far. Maybe put a smidgen of epoxy on the pair that are loose too. Good work.

[SeanB]

Tap will work, especially a thread forming one, but that is one seriously tiny tap there. Especially the price of nearly $30 each. Tiny screws as well, and a 0 Phillips as well, but at least they will hold better than the stakes, and less stress on the material as well.

[AF6LJ]

Looks good so far. Maybe put a smidgen of epoxy on the pair that are loose too. Good work.

I am going to try that on the one you see in the last picture, while it is still intact the contacts are working loose. The only issue is the piece is made of ether nylon or delrin. and the epoxy will stick but not too well. I also have some CA glue and was thinking about trying it on the other rotor in a location where it won't matter if it should stick better than I thing it would.

[AF6LJ]

Tap will work, especially a thread forming one, but that is one seriously tiny tap there. Especially the price of nearly $30 each. Tiny screws as well, and a 0 Phillips as well, but at least they will hold better than the stakes, and less stress on the material as well.

Next month I plan on ordering the screws, a few drills and a tap.
I have 1-72 screws but I believe they are a little too large for this application.
As for taps, I had not thought about using thread forming taps, I can use thread cutting taps and use a little soap or silicon oil to lube the tap. Because of this being plastic petrochemicals are to be avoided.

[cncjerry]

Tap will work, especially a thread forming one, but that is one seriously tiny tap there. Especially the price of nearly $30 each. Tiny screws as well, and a 0 Phillips as well, but at least they will hold better than the stakes, and less stress on the material as well.

You can buy taps that size in a hobby store for cheap.  They aren't made for steel or aluminum but work in plastic.  Also, you don't even have to tap them;  just let the screw form the threads.  Use socket head cap screws so you can put a lot of pressure on them while twisting them in.

[AF6LJ]

Tap will work, especially a thread forming one, but that is one seriously tiny tap there. Especially the price of nearly $30 each. Tiny screws as well, and a 0 Phillips as well, but at least they will hold better than the stakes, and less stress on the material as well.

You can buy taps that size in a hobby store for cheap.  They aren't made for steel or aluminum but work in plastic.  Also, you don't even have to tap them;  just let the screw form the threads.  Use socket head cap screws so you can put a lot of pressure on them while twisting them in.

I am going to tap the threads, my reason for doing so is to lower the stress on the thirty plus year old plastic.

[AF6LJ]

Just a quick update;
I took apart the front panel module for the 8569A Someone repaired the switch rotor with epoxy, I'll post pictures later on, I have to get the day started and will have pictures up later today or tomorrow.
EDIT;
Here is a picture of the glue job that was done on this rotor.

I think I can make this work........

This is good news.
I have some fresh JB Weld and my trusty hair drier....
For the time being I am going to get one good front panel assembled for my partner in this project and get him a working analyzer.
I should be able to make one good front panel from the remaining parts.

Sometimes I like Mondays
 

[cncjerry]

Use a little silicon oil or Vaseline on the tap.  You want it to cut and not stick. Depending on what is on the other side, it might be easier to just drill thru and use a bolt and nut instead of small screws.

[xrunner]

Just a quick update;
I took apart the front panel module for the 8569A Someone repaired the switch rotor with epoxy, I'll post pictures later on, I have to get the day started and will have pictures up later today or tomorrow.

When I first glanced at that pic, I was pretty sure you didn't do that repair. 

Is having a new part made with 3D printing an option? I know some of those systems are not that precise, but couldn't a laser 3D printer make a new part (if the file could be created) with new posts for the contacts? I don't know ... 

[AF6LJ]

Just a quick update;
I took apart the front panel module for the 8569A Someone repaired the switch rotor with epoxy, I'll post pictures later on, I have to get the day started and will have pictures up later today or tomorrow.

When I first glanced at that pic, I was pretty sure you didn't do that repair. 

Is having a new part made with 3D printing an option? I know some of those systems are not that precise, but couldn't a laser 3D printer make a new part (if the file could be created) with new posts for the contacts? I don't know ... 

I think that might be overkill, and I think I have found the right formula to make this happen. If Keysight had the parts I would consider ordering them.

[xrunner]

I think that might be overkill, and I think I have found the right formula to make this happen.

Yea but my middle name is Overkill, that's what I'm known for LOL. 

If Keysight had the parts I would consider ordering them.

I bet you would be horrified at the cost though, even for that small part. I got an Agilent E4411B Spectrum Analyzer last year - great unit. It's B&W, but it actually can display colors if you go into the right menu and change all the assignments for traces and this and that different colors. Takes a while. 'Cept the problem is it won't store all those colors and next time you turn it on - it's back to B&W. I looked at what it would take to make it remember the colors. It takes a firmware upgrade - but to do that you have to get the software from Keysight, and then before that, you must upgrade the memory, and to do that would cost somewhere between $1k and $2k. All to make it display colors. The thing didn't even cost me that much. Grrrr.

[AF6LJ]

I think that might be overkill, and I think I have found the right formula to make this happen.

Yea but my middle name is Overkill, that's what I'm known for LOL. 

If Keysight had the parts I would consider ordering them.

I bet you would be horrified at the cost though, even for that small part. I got an Agilent E4411B Spectrum Analyzer last year - great unit. It's B&W, but it actually can display colors if you go into the right menu and change all the assignments for traces and this and that different colors. Takes a while. 'Cept the problem is it won't store all those colors and next time you turn it on - it's back to B&W. I looked at what it would take to make it remember the colors. It takes a firmware upgrade - but to do that you have to get the software from Keysight, and then before that, you must upgrade the memory, and to do that would cost somewhere between $1k and $2k. All to make it display colors. The thing didn't even cost me that much. Grrrr.

I love overkill, I just don't have the money for this project...

I am sure their parts carry a high degree of pride, therefore they most likely sell $5.00 panel screws...

I have penetrating oil in the set screws of two knobs....
Hopefully tomorrow they will break free.

[Radio Tech]

Looks like a lot of mechanical repairs are in the process Sue. 
I hate those hot stakes the HP uses in their older equipment. My HP 8640B had the same issue but was on a set of gears that were clear on color. Since I have been into RC planes for 30 years and had a supply of micro hardware I was able to drill mine and use a nut and tap to hold the fingers in place.

But there was a major problem. I had no fingers left to bolt on. So I made them from scratch by using the contacts arms from a relay. Was a lot of work.
Will be keeping an eye on your project.

[AF6LJ]

I think I have enough parts to make two of them work.
If not I will improvise.
I'm going to have to see if I can talk Pat into a trip to Apex...
You may have seen Dave's video on that place....
It's Disneyland for our kind of folk.

[AF6LJ]

Time to get back to work...


The removal of the reference level and attenuator switches are well explained in the manual.

The 0-11DB fine level control leads are unsoldered.

This stop mounted on the IF gain shaft stays in place.

From here on out the disassembly is straight forward.

Input Attenuator contacts.

IF gain contacts

Okay parts to clean up and time to start gluing contacts in place.
More to follow in the upcoming days.

[AF6LJ]

Work can continue, we have two usable rotors, this analyzer can be assembled without any major component level rework.

The old dowel pin was removed and installed in the attenuator rotor

They are ready for installation....
Time for a break and later today clean up will begin on the old parts.
The PCB has some contact cleaner residue that will be removed with denatured alcohol.
The only items that need grease are the detent ball and spring.

[Radio Tech]

Looking good Sue.  HP sure loved to use those fingers on stake pins.

[xrunner]

Looking good Sue.  HP sure loved to use those fingers on stake pins.

Ditto. Can't wait to see it working. 

[AF6LJ]

We are getting there....
Found another fingerstock on the bench today...
I hope it didn't fall out of the switch rotors I have replaced.
The two I am installing in the IF gain and input atten... are tacked in place with a little CA glue to give them some extra holding power.
I have radio club paperwork to take care for the first three days of this week so it will possibly be Thursday when I get back on this.

[AF6LJ]

Looking good Sue.  HP sure loved to use those fingers on stake pins.

It is a good way to build a switch, and the labor is minimal.
No lugs to attach wires to, no switches to mount in to a PCB where alignment between the panel and the switch could be a bit too critical....
And the hot stakes lend the rotor assembly to automation.

Watched your Apache video today...
I might have tried a piece of braid and secured it with those screws and flat washers.
What you did was good. 

[Radio Tech]

Cool deal 

Hmm, I did not think of braid. You could also solder the two ends together.
Just may be something to play with.
I am pretty excited about this old rig.

[AF6LJ]

Cool deal 

Hmm, I did not think of braid. You could also solder the two ends together.
Just may be something to play with.
I am pretty excited about this old rig.

I would avoid soldering it, except at the very end to keep it from coming unbraded.

[AF6LJ]

Just finished putting the attenuator switch back together, took two attempts to get it right.
This is one time where following the HP assembly instructions were not the easy way to get the job done.
Allergies today, I have a splitting headache, pictures tomorrow.
Stay tuned.

[AF6LJ]

I was rather far along on completing the assembly of the front panel manual when I discovered the frequency span switch was two positions short.
So from this point....



I get to remove a few parts and re align the frequency span switch rotor with the detent.
It's not really a big deal, but it does involve some work.
Fixing it shouldn't be a big problem, we shall see.

Stay tuned.

[AF6LJ]

Oh and before I forget...
I will be doing a somewhat in depth teardown...
I need to do a good inspection and make sure there are no floating washers or switch contacts in the unit that could not be shaken out.

[Radio Tech]

Will be waiting on the next task Sue.
I know what you mean about a good tear down inspection.  So many things could be in there waiting to ruin your day!

[xrunner]

Cool! I remember having one of these in the lab at work, looking forward to many pics. 

[bitseeker]

I missed this back in March. Onboard now for the rest of the saga. Go Sue!

[AF6LJ]

Plenty of pictures to come.
A comment on the manual.
It does a fairly good job of guiding you though assembly and dissambly, there are parts in the manual that have you with your hands really full...

There will be little to no consequence to swapping around front panel parts, the only adjustment on the front panel that is not adjusted from the front is the external mixer bias zero adjust pot.
I haven't looked up the procedure but this analyzer won't be used with an external mixer for the foreseeable future. I'll do it anyway according to the book.

The manual is easy enough reading for someone of intermediate skill level, it is actually pleasurable to read.

Stay Tuned.............

[tautech]

Since the freely available manuals online were garbage, to put it nicely, I want to Artek Manuals http://artekmanuals.com/ and picked up the three volume set for a very reasonable price (under $20.00USD) and received a wonderfully scanned manual set.
These guys are great and the price is so reasonable....

Yep you can't beat a hardcopy for a job like this.

Remember you talking about these coming up and don't know how I missed it. 
Following.....

[KD0CAC John]

Hay Sue ,
I have 3 of the HP 8640B's and have the stake type sw. also and plan on touching up with a little epoxy to prevent loss .
Thats aside from buying used / supposed working , no output - just another project added to pile .
Nice repair post .

John
KD0CAC

[AF6LJ]

Since the freely available manuals online were garbage, to put it nicely, I want to Artek Manuals http://artekmanuals.com/ and picked up the three volume set for a very reasonable price (under $20.00USD) and received a wonderfully scanned manual set.
These guys are great and the price is so reasonable....

Yep you can't beat a hardcopy for a job like this.

Remember you talking about these coming up and don't know how I missed it. 
Following.....

I wish I had a hard copy, I bought a good scan of all three manuals, and it is almost as good with the benifit I don't have to figure out where to lay the manual while I work on the thing.

[AF6LJ]

Hay Sue ,
I have 3 of the HP 8640B's and have the stake type sw. also and plan on touching up with a little epoxy to prevent loss .
Thats aside from buying used / supposed working , no output - just another project added to pile .
Nice repair post .

John
KD0CAC

My goal is to have two of these 8640s there are good reasons to have two...
Then again, one of my favorite boat anchor HP sig gens.......
And it really is a Boat Anchor is the HP-8660, a real classic in the synthesized signal generator category, and most likely a career keeping one running.

[KD0CAC John]

Forgot to mention , 2 of the 8460's were parts units , the 3rd was sold a good but no RF output , in the 1st page of testing the meter shows voltage , but once the manual switches to RF AM , FM then there is no meter movement .
Thanks for the link to manuals , was able to find one I need - IFR A7550 , that was also sold as working & is not , so have the manual coming .

[AF6LJ]

The resolution bandwidth / frequency span switch issue is fixed, moving on to attaching the knobs and with any luck tomorrow I will have a working spectrum analyzer on my bench....
Then I will move on to the tear down and inspection before power up.

[AF6LJ]

Forgot to mention , 2 of the 8460's were parts units , the 3rd was sold a good but no RF output , in the 1st page of testing the meter shows voltage , but once the manual switches to RF AM , FM then there is no meter movement .
Thanks for the link to manuals , was able to find one I need - IFR A7550 , that was also sold as working & is not , so have the manual coming .

I think having an HP-8640 parts mule or two is a good idea.

[AF6LJ]

The front panel module is assembled and all that need be done is clean off a little flux.





After I clean up my bench tomorrow we shall do a tear down and inspection.

Stay Tuned..............

[xrunner]

Stay Tuned..............

Oh yea! I remember that green accent for certain buttons. And the gold traces too. Man I can't wait to see it in operation! 

[bitseeker]

I am properly tuned to this channel.

[AF6LJ]

I am properly tuned to this channel.

Getting close to the end of this project.
Pictures to come, I had to work over the Reference level control group and I have it properly aligned now and am engaged in reassembly of the front panel module.
Getting those hubs aligned properly is challenging but I finally have the knob engaging the input attenuator properly and returning to it's home position in the IF Gain rotor.

Stay Tuned............

[Radio Tech]

Exciting.... 

[AF6LJ]

It's up and running, pictures coming soon....

[AF6LJ]

It took some doing but I finally got the reference level switch and the attenuator to work well together.



Tear Down Pics coming..

[AF6LJ]

Tear Down pics...
I won't comment too much the board IDs are etched on the boards.
So here goes...

Mixer and YIGs are in the lower left..




High Voltage and deflection...


Everything is well labeled.




Main power supply...


Input attenuator in the upper left, relays for signal switching and lots of plumbing.

[AF6LJ]

CPU board the 6502 in the upper left...

[AF6LJ]

Sorry...
I think that is all of them.

[xrunner]

Beautiful green display - and look at all the blue pots! 

Great work!

[AF6LJ]

There ya go 65 Pounds of LOVE

[bitseeker]

Wow, quite a row of cans in the power supply, and trimmers on the current sensing board. Lots of neat stuff in there. Congrats on the repairs, Sue.

[tautech]

Isn't it great to see so few polarised timebombs caps on PCB's. 
Might just see you out girl. 

[AF6LJ]

Wow, quite a row of cans in the power supply, and trimmers on the current sensing board. Lots of neat stuff in there. Congrats on the repairs, Sue.

There are two boards in there one with the most pots on it controls the YIG tuned oscillator.
The other one os for the YIG preselector.

[VK5RC]

Lovely work on a lovely machine - long may she reign!

[rdkrco]

I also want to buy one of those rotor contact "fingers" if a source can be found. Otherwise I may buy an entire broken HP vintage Spectrum Analyzer just for the rotor contact fingers.

[Radio Tech]

So nice to see it come together Sue. Really nice work you performed on this unit.

 

[AF6LJ]

I also want to buy one of those rotor contact "fingers" if a source can be found. Otherwise I may buy an entire broken HP vintage Spectrum Analyzer just for the rotor contact fingers.

Until I realized I had enough I was looking at finger stock over at Mouser, and found some viable candidates.


To Everyone else thanks for the kind replies.

[cncjerry]

what's with all those pots on that one board?  looks like it would be a real hassle to align.  Nice job by the way.

[AF6LJ]

what's with all those pots on that one board?  looks like it would be a real hassle to align.  Nice job by the way.

That is to set the current going into the YIG osciallator tuning coil...
All those pots make for a linear change in frequency...
It is a current shaping network.

[WastelandTek]

oh man, when I heard about the photobucket fiasco I knew there would be really important threads that ended up like this

    

[bitseeker]

Sadness, indeed. 

[AF6LJ]

I'm not real happy about this, and will start using the Google Photos page...
I have another ongoing project over on the QRZ forums and Google photos will let you link to your photos.

[WastelandTek]

I'm not real happy about this

yeah, I bet

I am so sorry Sue.  I know it is a lot of work, but are you planning to relink the thread?  These kinds of threads are sooooo useful for people later trying to fix similar gear.

[AF6LJ]

I'm not real happy about this

yeah, I bet

I am so sorry Sue.  I know it is a lot of work, but are you planning to relink the thread?  These kinds of threads are sooooo useful for people later trying to fix similar gear.

I still have one more to rebuild, maybe two if I have enough parts....
I may repost the pictures then.

[bitseeker]

Ooh, more rebuilds. Looking forward to it!

[AF6LJ]

Ooh, more rebuilds. Looking forward to it!

The next rebuild will start next month with new pictures.

[bitseeker]

Thanks for the update. Looking forward to it.

[WastelandTek]

yayyyyyyy!!

new pictures!

[AF6LJ]

I am finishing off a project now that is taking up a lot of valuable bench space. (Heathkit HL-2200 linear amplifier). This amplifier has been giving me fits on the ten meter band. Looks like I have a bad input circuit cap, parts ordered and soon enough this project will be done.


Status Update;
We left off with the sweep time knob being stuck on the shaft. This was stopping the removal of the front panel dress plate. and the rest of the rebuild process of the second front panel.
I picked up two left hand drill bits and a 4-40 (right hand) tap) I was able to free up the hex head set screws in the knob, with the threads in the knob insert suffering little or no damage.
SO...
This repair will begin with the remaining disassembly of the front panel module.
I have learned a few things from the assembly of the last front panel module and this one should go with a minimum of rework to get things to align up right.
Here is a sample of what is in store


And the back side....


These were taken from the first rebuild.
I do need to get the picture size down to something like 1024 X 768....

[bitseeker]

Interesting mechanicals back there. I wonder when 3D printing will become a staple of the bench to keep these vintage instruments going.

[AF6LJ]

Quote from: bitseeker on Today at 12:02:51 PM

Interesting mechanicals back there. I wonder when 3D printing will become a staple of the bench to keep these vintage instruments going.

The knobs are fragile, but the switch rotors inside are robust.
The problem is the little metal contacts get lost.

I would love to find a source for those little contact fingers.

[bitseeker]

Yeah, not so easy replacing little metal bits of various kinds. I suppose one could learn to work with spring steel, but I have no idea what that involves to cut, form, etc.

[WastelandTek]

are there pics up there that I am not resolving for some reason?

[bitseeker]

Reply #80 has pics, but the one for #82 seems not to be set for public viewing.

[WastelandTek]

hmmmm, I better look at my noscript settings, all the other pics on this forum are working for me

[AF6LJ]

are there pics up there that I am not resolving for some reason?

I use to post all my pictures to Photobucket...
Now I keep them in my Google album.
Photobucket decided they wanted to charge an arm and a leg for the bandwidth used by people viewing linked images.

[AF6LJ]

Yeah, not so easy replacing little metal bits of various kinds. I suppose one could learn to work with spring steel, but I have no idea what that involves to cut, form, etc.

It's not really that bad, although this time I get to do a lot more of gluing those contacts in place. I have been thinking about drilling and tapping the locations where the broken hot stakes are at. Using 0-80 screws as clamps to hold the contacts in place while the glue cures.
We shall see how this goes.

[VK5RC]

I have a friend who is a dentist, he is a glue and material 'king', some wisdom he passed on was that he often uses a tiny sand blaster (about pencil sized)  to lightly etch materials before gluing.

[AF6LJ]

I have a friend who is a dentist, he is a glue and material 'king', some wisdom he passed on was that he often uses a tiny sand blaster (about pencil sized)  to lightly etch materials before gluing.

You almost have to ether chemically etch or manually etch the surface if you want success with glues. Making the surface a little tacky also helps.

[AF6LJ]

Work has begun on the second HP-8569B front panel module. This one isn't as bad off as the last one, I think there is only one switch contact assembly that needs repair.
As you remember I had to drill out the two set screws in the sweep time / div knob and chase the threads with a 4-40 tap.
Today I have removed the PCB assemblies from the front panel plate and removed the dress plate.
So here is where we are at.



On this unit the Frequency span switch is missing a set of contacts. This requires the rotary switch on the right must be completely taken apart and the rotor prepared to have the switch contact (I managed to save several) glued in place.
With that switch removed I can inspect the input atten., and IF gain switches for missing contacts. There is an issue with the vernier knob, the pot works but the on screen readout isn't working reliably. The contacts for the rotary encoder are there, my thoughts are some adjustment of the wheel that holds the contacts may be in order.

More tomorrow, I need to dig the boxes of parts from the other front panels out of storage.
Be prepared for lots of fresh pictures.

[xrunner]

Cool - pics are good eye candy. 

[WastelandTek]

does anyone know which script is associated with these pics...I'm not resolving them and the rest of the site works fine

[AF6LJ]

I am using FireFox and they look fine.

[Yansi]

Hi guys, would you mind please NOT to link externally hosted pictures into the forum? What I now  see is only a bunch of cats from a f'kin photobucket instead.

[AF6LJ]

Hi guys, would you mind please NOT to link externally hosted pictures into the forum? What I now  see is only a bunch of cats from a f'kin photobucket instead.

The photobucket account is gone, they no longer support external linking without a costly subscription. That is unfortunate. I will continue to use my google photos account, since this site doesn't support uploading high resolution photos.

[WastelandTek]

I am using FireFox and they look fine.

Yes, I am using firefox as well, something in my suite of script/ad/track blockers is nerfing your photos.

Where are you hosting them?

[AF6LJ]

I am using FireFox and they look fine.

Yes, I am using firefox as well, something in my suite of script/ad/track blockers is nerfing your photos.

Where are you hosting them?

Google Photos.

[bitseeker]

The photos appear OK for me on Firefox with uBlock Origin. The images come from googleusercontent.com. Check if your blocker is preventing content from that domain from loading.

[AF6LJ]

More work on the way, I have a bunch of Radio Club paper work I have to get done. I will be back ASAP.

[AF6LJ]

Here is how to disassemble the bandwidth and frequency span switches.
I cannot stress the importance of proper tools.
A set of combination wrenches in imperial sizing.
Allen wrenches GOOD ONES! this is no place for cheap tools, some of the set screws are very tight and you don't want to have to drill them out and chase the threads with a tap.
Before I forget... the case screws are posidriv. not Phillips.
you will need a small pair of outside snap ring pliers for the reference level control group.
A copy of the service manual (volume 3)

With the proper tools, and a reasonable mechanical aptitude anybody, even someone partially sighted, like me can repair these switches.
Some operations may require not drinking that third cup of coffee.

The next post will contain pictures of the disassembly of the bandwidth and frequency span switches.

[AF6LJ]

I reposted the above picture in order to show the back side of the bandwidth / span switch..\
The shaft can be seen in the center of the module just above the blue connector.


Turn the two switches ether full clockwise (engaged) or full counterclockwise this will establish a reference to make reassembly easier. After you do that make witness marks on the side of the switch rotors to document their position. (you will regret not doing this.)
I did go back and scratch in lines with an awol just in case the marker rubs off. Also notice the position of the two support pillars on the switch rotors. If you have a camera take loads of pictures if you have any question as to how things go back together you will have them...
Next post...

[AF6LJ]

The wires connecting the sweep time board to the main switch board need to be un-soldered.
There are two screws holding the board to the top of the rear switch rotor, this rotor is the bandwidth rotor and has only one set of fingers.....



Here is a view of the bandwidth switch rotor, this one has its contact fingers intact. Take note of the spacers and washers under them. remove them and place all your parts up to this point in a safe place. I use Altoids boxes.
The screws used to remove the front panel assembly are in one. In another are all the hardware removed to disassemble the module. Now it is time to start one dedicated to this stage of the process.


Here is a view of the switch rotor removed. BE VERY CAREFUL OF THE BALL AND SPRING. These can get away from you if you are not careful.

You can see the spring and socket on the rotor where the ball resides when the switch rotor is installed on the shaft. Don't move anything just yet........
Take careful note of the pin protruding out of the side of the brass collar... and the location of the stop pin. This is where the grief can begin if you haven't documented their relationship to each other.
Next post............

[AF6LJ]

Here you can see a small scratch I made to indicate which hole the pin is point to. This witness mark is needed to orientate the pin which engages bandwidth rotor when the knob is pushed in. That pin is what turns the bandwidth knob. Likewise you will find a similar pin on the frequency span rotor which will disengage when the knob is pushed in, leaving the frequency span knob in its current position.
It is now okay to remove the spacers, washers and the bandwidth switch detent, note the position of the notch.

Moving on...


On the other side there is an E clip and washer that needs to be removed.
I use an awol to remove the E clip, be careful not to loose this or the washer.

The shaft will not come out just yet, you have to loosen the two set screws holding the brass collar the stop pin is located in. Now the shaft will come out but be careful.
The frequency span switch detent must be supported while this shaft is removed. Use your hand to support the switch detent and screws, there is another ball and spring you must keep an eye on.


Take note of the spacers and washers. Also take note of the collar location, at the end of the hallow shaft. In this picture I am supporting the switch detent and screws with my hand while loosening the second set screw on the collar.

Next post......

[AF6LJ]

Hardware from the bandwidth switch assembly.
You should have all this. for that switch plus the rotor and spring.



Here is the front view of the frequency span switch, note the position of our witness mark to the pin on the brass collar. also note the spring in its cup.



Here are the pieces from the frequency span switch.
You can add a witness mark to locate the pin position, or simply remember it is in the center of the rotor stop block.

Moving on.......
Next post...........

[AF6LJ]

In the above picture you can see the top side of the switch rotor. One set of contacts remain, the outside set has fallen off and these can be found inside of the analyzer if you are careful it can be recovered.



Above you will see the components from the frequency span switch. A collar that is held in place with a spring clip the spring, ball, spacers, screws, detent, and shaft.
The missing contact finger set was recovered when the analyzer was opened.



Here you can see where the missing contact finger set goes.
We will go into reattachment in a later post, I have to deal with other obligations for the next few days. Any questions post them and I will answer them as I visit this site several times a day.

[xrunner]

Great pics I'm sure they will help someone someday. 

[AF6LJ]

Great pics I'm sure they will help someone someday. 

Thee is an individual who has contacted me about the same repair, he may or may not post in this thread.
If he does he will want to start his reccmonded reading on page 8-25 of volume three of the manual.

[AF6LJ]

So after fending off life's oblations I now have a few hours to work on the switch rotor repair.
Using my Redneck engineering talents I rigged up a holding fixture for the switch rotor.
What I did next was to practice holding and landing the switch contact fingers in the proper position. (Keep a reasonable distance from the coffee pot before attaching these contacts.)


A bottle of CA glue was opened and a test drop applied to the body of the fixture to prime the spout... Then a drop was applied to the location where the contacts would be attached, the bottle sealed and the contacts which were preloaded into tweezers were applied and held in position for two minutes.

Tomorrow afternoon the surface of the glue joint will be scuffed and lightly cleaned. Epoxy will be applied to the joint to reinforce the joint, and provide enough bonding straight to allow for reassembly of the front panel module and installation this weekend.

[AF6LJ]

Okay the CA glue has set up and cured now it is time to apply epoxy.
The surface is roughed up, and cleaned.
Out comes the hair dryer the epoxy and cotton swabs..




The switch rotor will now sit under an incandescent lamp for several hours to speed up the curing process and to help drive off moisture.

Stay Tuned reassembly is next.

[xrunner]

Stay Tuned reassembly is next.

Interesting work! I'm going to be glued to this thread until the final results. 

[bitseeker]

Thanks for the detailed log, Sue. Very educational. Looking forward to reassembly and power up.

[AF6LJ]

Thanks for the detailed log, Sue. Very educational. Looking forward to reassembly and power up.

Thanks; I enjoy doing these...

[AF6LJ]

This morning the the resoluation bandwidth and frequency span switches were reassembled. Pictures will be posted later on...
I am going to take a moment and warn people about the assembly procedure in the manual....
It's not necessarily right, so far of the two 8569s I have rebuilt switches in the front panel assembly was slightly different on both. This makes it all the more important that you take photos especially of how the hardware stacks up on these switch assemblies.
The pictures I took were valuable in the reassembly process.

[bitseeker]

Yeah, I always take photos when doing stuff like this. They can always be deleted if the job turns out not to require them for reassembly. Fortunately, we don't have to rely on film cameras these days.

[AF6LJ]

Just an FYI
I finished repairing the second HP-8569B this morning, works well...
I have pictures to post and will be cleaning up this thread, to get rid of the empty place holders and such.

The thread will bet cleaned up later in the week, I will walk through the process of repairing these switches and I shall repost teardown pictures at some time in the future, given that I have a pair of hanger queens now (they really only need front panel parts and knobs. ) I can do the teardown pictures with a bit more detail.

[bitseeker]

Sounds great. Thanks, Sue, and congrats on the happy patients.

[xrunner]

Just an FYI
I finished repairing the second HP-8569B this morning, works well...
I have pictures to post and will be cleaning up this thread, to get rid of the empty place holders and such.

It's a bummer that you have to do that clean-up but it will be a great help to others in the future. 

[KD0CAC John]

Hay Sue , John KD0CAC here .
I have 2 parts units got cheap , and then bought one that was spouse to work , well partially .
With the 3 I have all options , including a riser board bolted in the 3 unit .
I have seen lots of these , mostly on line and most are missing a cover in the top right rear , seem to be a common part left out during ? whatever ?
Oh and have not seen you around another hang-out for some time , hope all is ok ?

[AF6LJ]

Hay Sue , John KD0CAC here .
I have 2 parts units got cheap , and then bought one that was spouse to work , well partially .
With the 3 I have all options , including a riser board bolted in the 3 unit .
I have seen lots of these , mostly on line and most are missing a cover in the top right rear , seem to be a common part left out during ? whatever ?
Oh and have not seen you around another hang-out for some time , hope all is ok ?

Everything is fine these days. That other hangout and I had differences and they decided we needed a divorce.

[KD0CAC John]

Good to know .
Ya stuff happens , some time I wonder if I'm getting close

[AF6LJ]

Good to know .
Ya stuff happens , some time I wonder if I'm getting close

There is a hand full of people over there who really don't like to see a woman who knows more electronics than they do. Then you have K6bbC; he single handily managed make that place one of the least desirable places on the Net. 

[KD0CAC John]

Sorry to see a good resource be lost to that site .
I haven't been hanging out here as much , so just having seen ya around .
It's too bad , I know the media in general is polarizing the masses , but there also seems to be more illness , hate going around .
To get back on topic , kinda - the thread title - spec. analyzer , I followed a Google search on the HP 8650B .
My newest one came from someone on the ZED , and did not have all functions , then more quit after looking into it more .
I've read that if in storage sitting on the feet on back / front facing up , that some lube ? in the main oscillator flows over time and you can loose the signal , have you come across this ?
   

[rob.manderson]

I'm guessing you mean the 8640B?  If so, yes, it's not good to store them on their front or back because the cavity lube flows.  I haven't seen it myself but I understand it can take months(!!!) to get back to normal.

Otherwise, a fine signal generator and you can have mine when you pry it from my cold dead hands! 

[AF6LJ]

My newest one came from someone on the ZED , and did not have all functions , then more quit after looking into it more .
I've read that if in storage sitting on the feet on back / front facing up , that some lube ? in the main oscillator flows over time and you can loose the signal , have you come across this ?
   

I have not heard of that, wow...

[AF6LJ]

I'm guessing you mean the 8640B?  If so, yes, it's not good to store them on their front or back because the cavity lube flows.  I haven't seen it myself but I understand it can take months(!!!) to get back to normal.

Otherwise, a fine signal generator and you can have mine when you pry it from my cold dead hands! 

I feel the same way, as a matter of fact I would love to have two.

[BravoV]

All photos are gone Sue, suggesting to use forum's attachment feature rather than external hosting.

[AF6LJ]

All photos are gone Sue, suggesting to use forum's attachment feature rather than external hosting.

Photos are too small when using the attachment feature.
When I have time I will repair the thread...

[WastelandTek]

It has been a long time, and I am well aware what a pain in the posterior repair of the thread would be, but I would like to plead with you to take the time for the sake of future restorations.

I had the pleasure of reading this thread before the photobucket fiasco and it was absolutely top notch.

[tautech]

It has been a long time, and I am well aware what a pain in the posterior repair of the thread would be, but I would like to plead with you to take the time for the sake of future restorations.

I had the pleasure of reading this thread before the photobucket fiasco and it was absolutely top notch.

+1100