I have started looking into aligning the 585A. Vertical alignment seems excellent, timebase alignment not so much. Lucky I have a freshly repaired and aligned Type 184! I was doing great till I got to the point of adjusting the .05 uS/cm setting. It seems someone before me fuxxored C348, which is the variable cap that adjusts the sweep rate for this setting. The screwdriver slot is totally broken off from the internals...it just spins.
Good thing the vertical amp is in alignment. You really don't want to mess with that cascaded type circuit unless you really have to.
I was wondering when you were going to find signs of Gorilla activity. Magilla seems to get around. It's a 3pf - 12pf trimmer. You should be able to come up with a replacement even if it isn't exact. As long as it covers most of that range you should be OK.
Edit.....I have some parts only plug-in's here. I'll check later today and see if one of them has a trimmer cap close to that value.
Yeah, it had to be somewhere. At least this one is an easy to get to... some of the others are buried pretty deep.
Thanks, that would be awesome if you have one. Feel free to drop me a message if you do and I’ll send you my address and such.
Here you go. 5.5pf - 18pf trimmer. Out of a 465 timing board. Not an exact match but should get you there. I tried testing it but not getting valid readings. The value is so small that stray capacitance is fooling the DMM. But I see no reason why it shouldn't be OK.
If you want it PM me and I'll get it in the mail tomorrow.
Sure the part is still OK ? Looks like from a slightly overpowered RF transmitter filter
If you look very well it even says FRIES
Recapping the 2465. All the RIFAs are gone already. Now what? Get rid of all the PSU elcos? They actually look in decent shape.. What about the ones on the analog board? Do they suffer much? Should they be replaced? Don't look too bad either...
Med has an EXCELLENT article on doing the recap starting here: https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1658102/#msg1658102
It breaks the regulator board and inverter board into 2 easily digestible sections in 2 posts.
Short version: You're going to replace all the electrolytics except the 2 huge blue axials. Also look for the little RIFAs & bead tants shown above and check those diodes (replace them all if any one is open or drastically different resistance than the others) and that resistor to make sure it hasn't shifted value, even if it doesn't LOOK toasted.
I've also attached a well-known .pdf of this service procedure from CondorAudio below; it is the source of the photo above. There are electrolytics on the A5 board that commonly fail causing electrolyte damage; it also has their locations.
Good hunting!
mnem
So... yesterday's Canada Post had 2 packages; it was package number B that REALLY made me go SQUEEEE!!!
As a result of goading by Kosmic (and because I felt a need for something NEW on the bench), I bought a MasTech 8911 just to see if it was as much better than my MS8910 as people say...Still waiting for mine. Everything is so slow these days.
Wanna come on down and play with mine for a while...? I'll BBQ up some pork chops and baked taters for dinner.
mnem
"ROAD TRIP!!!"
I hate the German Telekom! Arrogant fucking incompetent bastards!
<RANT>
I hate the German Telekom! Arrogant fucking incompetent bastards!
To be exact: I hate some of ther managers, which decides dumb things!
But let me tell the story from the beginning ...
What we have:
- A friend of mine, let's call her Bärbel
- me, as the guy who knows one or two things about Internet, DSL, IP, administration etc.
- a place at the edge of known civilization where Bärbel is living
- German Telekom
- German Telekom hotline
- the guy at the hotline, let's call him Mr. Hardison
Bärbel needs internet access and asked me, if I could help her with this stuff, because she's not very experienced in this kind of technical things. Okay, why not, sounds like an easy job.
I checked, what the available options are at her place. No DSL available via copper wire. Fibre will be available in two or three years, so the only option left was this LTE "Magenta für zu Hause" (magenta at home) from the German Telekom.
Ok, fine. Did a list of the hardware needed:
- AVM Fritz!Box 6890 for the LTE connection
- 2x media converters copper - fibre
- 1x AVM Fritz! Repeater 3000
- 1x Fritz!Fon C5
- 50m fibre cable with plugs
I need to place the 6890 directly under the roof of the house, because otherwise there will be no radio reception because of the dead zone because of the geography where she is living (end of a valley with some high hills nearby). Edge of civilization.
The plan is to connect the repeater in her appartment via the fibre cable with the 6890.
This week all gear arrived and I set it up in my lab for configuring and testing.
All worked well except for one thing: this bloody phone is refusing to connect.
So I called the hotline of the German Telekom and after listening to this Warteschleifengedudel for about 45min, Mr Hardison picked up my call. I explained him the situation and he did some checkings . After some discussions with him (and him with his boss), he concluded to this:
I need to connect the 6890 to the telephone line connection box. VoIP via LTE is not possible.
[...]
WHAT?!?
I asked him, if he is really serious about this.
He confirmed.
Twice.
With his boss.
The German Telekom is NOT able to do VoIP traffic via an LTE connection.
To be clear: Mr. Hardison did a very good job and he couldn't understand either, why this shouldn't be possible.
May those bloody bastards of incompetent, dumb and arrogant managers from the German Telekom burn in hell for this stupid decision!
Together with a 24/7 acoustic irradiation of their Warteschleifengedudel from evil madness!
Now I have to explain this to Bärbel, that we need another wire because of the incompetence of the Telekom.
Really! I hate the German Telekom. Parts of them.
</RANT>
Now I'm feeling a little bit better.
Thanks for listening.
Warteschleifengedudel = hold/elevator music in a waiting loop
Got C-4...?
mnem
You might need something thin to slip between the halves to start jimmying it. If it's anything like HP directional couplers such as the 778D it's a little fortress and will not come apart easily.
Guys & gals, whats the point of having more than one of GPSDOs ?
Guys & gals, whats the point of having more than one of GPSDOs ?
Was just reading the Condoraudio document. CAN SOMEBODY PLEASE JUST TELL ME I NEED TO REPLACE A SINGLE CAP AND ALL WILL BE FINE???
Spent a couple of hours today, going through the pile of stuff i acquired during my last trip south. First up was an unlabeled directional coupler, which worked and appears to have a bandwidth of 500MHz to n GHz, where n is greater than 2 (the top end of my SA). Next was a HP 33304 11dB programmable attenuator, for which I can find no documentation, so I set it aside.
<RANT>
I hate the German Telekom! Arrogant fucking incompetent bastards!
To be exact: I hate some of ther managers, which decides dumb things!
...
<RANT>
I hate the German Telekom! Arrogant fucking incompetent bastards!
To be exact: I hate some of ther managers, which decides dumb things!
....
I need to connect the 6890 to the telephone line connection box. VoIP via LTE is not possible.
[...]
</RANT>
Was just reading the Condoraudio document. CAN SOMEBODY PLEASE JUST TELL ME I NEED TO REPLACE A SINGLE CAP AND ALL WILL BE FINE???
Yes, you can replace a single cap and all will be fine. Provided you replace the correct cap, that is