HP 5335A Timer / Counter - Anything i should know?

[Orange]

Change A4C36 from 10µ/10V to 22..47µ/10V. Correct value depends on tolerances in the circuitry, and on the capacitors leakage current.
This will increase "Gate Mode NORM"  time from (20ms..4s) to ca. (50ms..12s), delivering max. 10 digits instead of max. 9 only.

Nice addition, I noticed that I get 11 digits now when it has to display 10.000002399 for example. It is clever in a way, because it jumps automatically from the
10. 000 000 00 notation to the ones without blanks. HP did now how to write software in the old days 

[Wim13]

Well I tweaked  one electrolytic, which controls the manual gate time, so that I could measure up to 12.5secs, (instead of only 1s), to get 10 digits from the front panel.
Otherwise, GPIB control would do the job, up to 11 digits.
Frank

Can you go into detail on this.

You can do this also by hand, use the manual open/close push button, under gate mode.
if you leave the gate open for hundreds of seconds you get more digits.

[Dr. Frank]

You can do this also by hand, use the manual open/close push button, under gate mode.
if you leave the gate open for hundreds of seconds you get more digits.

That's correct. 100s will give 11 digits resolution, but that's it.
For even longer times, say 1000s, the counter will not output more than 11 digits plus the trailing "1" maybe, neither on the display, nor over the GPIB.

That's a pity, as the counter internally counts and calculates to 20 digits, or so.

[Dr. Frank]

Following a hint from the usual manual storage, the version 1.1 can be identified by the start up message of the GPIB address.
The (additional) decimal point before the address is displayed only for the V1.1

I got a 1988 counter, but 1987 firmware, presumably already the V1.1, although it is still in two EPROMs. Well, now I wonder if I should see 2 decimal points...

Perhaps owner of the old version may take a notice if the GPIB address is completely without decimal points.. I.e. "HP-IB Addr 18" or

"HP-IB Addr. 18"


And what is the "MK 36000 time bomb"?

[Orange]

OK, so I changed the EPROMS from V1.0 to V1.1. Initially done some tests on Channel A  and B, and all seems fine...

Later today I checked Channel C    With a 100MHz signal it displays 320MHz !, 1200MHZ gives 3840MHz on the display !

I presume that the later units have a different division factor for the Channel C board which is compatible with V1.1
I could not find this in the documentation.

So its back to V1.0

[Orange]

And what is the "MK 36000 time bomb"?

My unit had a MK36xxx ROMs. They are notorious for sudden failure. Lots of units of HP and Tektronix have them. If you ever have a unit with them, and the unit does not work while everything else is OK, it might be the dreaded ROM syndrome. Mostek did a bad job with these suckers.
They basically loose their content, also known as ROM rot

 

[Dr. Frank]

Yes sorry, I'm a bit late.
I had to study all the change history in manual 05335-90044, up to Serial Prefix 3154.

V1.1 had been introduced in June 1984, for all instrument with 2424A06001 and above.

V1.1  has one decimal point in the HP-IB string, as shown with my instrument.
V1.0 shows no decimal point in the GP IB string at all.

I already have the newer prescaler  in the C-channel (05335-60034), which divides by 64.
The old prescaler (05335-60009) divided by 20 only, therefore the firmware has to match.

It's not clear, if there exists an intermediate firmware which corrects all the bugs of V1.0, but is made for the old prescaler, i.e. multiplies the result by 20 instead of 64.

The difference may be inside the EPROM A4U22, as 05335-80012 (as in my unit) refers to the new /64  prescaler, and 05335-80006 refers to the old /20 prescaler.
That's change 7 in this manual, and affects prefix 2820, exactly my counter, and also for retrofitting the newer C-channel option 030.


Obviously, I have an intermediate A4 version, 2 EPROMs - but V1.1 and the newer prescaler. Perhaps my instrument had been updated, or the C - Input had been replaced.

I could not find a comprehensive table, which EPROM code refers to which firmware version, and/or to which prescaler.
Frank

[Dr. Frank]

Well, my instrument also needed a new fan, but I bought one from papst again.

In my version, the 110V type had been replaced by a 24VDC / 36CFM one, as shown in the photographs.
It is fed by the unregulated + or - 25V. Got no schematic for that change.

I chose an 8414NGM, 80x80x25mm,58m3/h, and it has 26dB(A) only.

Frank

[Orange]

My unit also has a Papst DC fan, its rated for 18 Volts, but it runs from 24 Volts !

Strange that official diagrams do not include this change. For sure it was build by HP like this.

I could change it for a Sunon Maglev, that should kill the noise 

[Dr. Frank]

My unit also has a Papst DC fan, its rated for 18 Volts, but it runs from 24 Volts !

Strange that official diagrams do not include this change. For sure it was build by HP like this.

I could change it for a Sunon Maglev, that should kill the noise 

This change from 110V to 24V is described in words, but I'm lacking the schematics.
So it was an official change, definitely.

The fan operates from 18 to 28V.

[PE1RKI]

mine also came with the papst rated 18 to 30 volt.
most ic date codes are 1989.
i got it from a danish company going bust for cheap.
but is has no 1300mhz option and no oven 
and thanks so much for the capacitor hint!!!!! 
i modded mine immediately

[Dr. Frank]

OK, so I changed the EPROMS from V1.0 to V1.1. Initially done some tests on Channel A  and B, and all seems fine...

Later today I checked Channel C    With a 100MHz signal it displays 320MHz !, 1200MHZ gives 3840MHz on the display !

I presume that the later units have a different division factor for the Channel C board which is compatible with V1.1
I could not find this in the documentation.

So its back to V1.0

Hi Oranje,

after reviewing all the pictures posted here, I think that max_torque has got the right combination of EPROMs for you.

The 05335-80006 for the elder by-20 scaler, and the 05335-80007 as in my unit.
If his unit displays the decimal point, then it should be the updated V1.1 also, especially as his unit is 2626A.

Perhaps he may read the content of both EPROMs for you and you'd give that try.

Frank

[Orange]

Well that's certainly worth a try.

I find it peculiar that HP never mentioned something about it. It's also a thing to remember if you want to upgrade your counter with a Channel C board.

[Dr. Frank]

Well that's certainly worth a try.

I find it peculiar that HP never mentioned something about it. It's also a thing to remember if you want to upgrade your counter with a Channel C board.

Hm, I got that latest manual ...90044, which really covers EVERYTHING.
The manual changes are described in reverse order, and very complicated to read.
The different schematics stages are missing, so you have to imagine these.

As I got a (very good) copy only, I don't know, how the original manual looks like.

But anyhow, I think the status is clear now.

Would be interesting, if you get the content and succeed to update correctly.
V1.0 has really many annoying GPIB related and function bugs.

Good luck.
Frank

[max_torque]

This is turning into quite an interesting thread! ;-)

Yes, my unit is V1.1 and displays decimal point on boot.  I'll try and upload the proms when i get a second 


I think i will install the fan mod too.  Mine is running from the DC bus, but boy is it noisy!  It's like someone doing the hoovering in the room 


Also, i notice the GPIB board "A7" is completely seperate from the logic board "A4" and consists of a GPIB driver, driven by some parallel data lines for address and data etc.  A nice little project would be to replace this pcb with a modern microcontroller with a direct USB output, to a USB socket on the front panel (probably on the right hand side)  That would neatly avoid all the messing around with GPIB->USB convertors etc!

If i find the time i might scope out some of the signals, however, assuming the driver IC on A7 is "dumb" then we should have TTL level GPIB protocol on the A7xA4 connector?

[Dr. Frank]

This is turning into quite an interesting thread! ;-)

Yes, my unit is V1.1 and displays decimal point on boot.  I'll try and upload the proms when i get a second 


I think i will install the fan mod too.  Mine is running from the DC bus, but boy is it noisy!  It's like someone doing the hoovering in the room 


Also, i notice the GPIB board "A7" is completely seperate from the logic board "A4" and consists of a GPIB driver, driven by some parallel data lines for address and data etc.  A nice little project would be to replace this pcb with a modern microcontroller with a direct USB output, to a USB socket on the front panel (probably on the right hand side)  That would neatly avoid all the messing around with GPIB->USB convertors etc!

If i find the time i might scope out some of the signals, however, assuming the driver IC on A7 is "dumb" then we should have TTL level GPIB protocol on the A7xA4 connector?

Hope your Eprommer can handle those strange EPROMs, they have another pinning than the 2764s.
So I can't read mine..

A7U1 is not a dumb GPIB driver, it's the 68488 GPIB controller, so I assume it contains also several timer, registers and perhaps a small state machine.
Edit: Yes, it's confirmed. datasheet still is online, and the chip contains a lot more of intelligence. Especially all those GPIB handshake signals and registers, DMA controller, and GPIB-488 command parser are covered.
Frank

[max_torque]

No, my EEPROMMER isn't "Old skool" enough to deal with the MCM68764 chip!  I'll have to knock up something with a micro to read them............

Ok, so if the GPIB board does have it's own intelligence driver, that means the interface between it and the main processor on A4 is even more likely to be fairly simple?

[Dr. Frank]

Ok, so if the GPIB board does have it's own intelligence driver, that means the interface between it and the main processor on A4 is even more likely to be fairly simple?

Well, the interface maybe simple, but the traffic on it is quite complicated as the 6802 µP has to program all that stuff inside the GPIB controller.
I see no chance to simply interface at that point, either.

Frank

[Wim13]

My 5335, serialnumber starts with 2032A, and has two NMOS roms type 2364
And also my advance (e)prom programmer has no option for these.

If you want, you have to make a conversion tool, it does not differ very much from a 2764,
so it is not difficult to make because you have only to read the 2364
I did that before to convert from some old TMS 2564 to 2764

I found with google some already designed conversion tools.

2364 Pinout compared to 2764

                                                2764
                                            +----\/----+
          2364                         Vpp        Vcc
      +- --\/----+                    A12         P
 A7 | 1       24| Vcc              A7           nc
 A6 | 2       23| A8               A6           A8
 A5 | 3       22| A9               A5           A9
 A4 | 4       21| A12             A4         A11
 A3 | 5       20| /CS              A3         /OE
 A2 | 6       19| A10             A2         A10
 A1 | 7       18| A11             A1         /CE
 A0 | 8       17| D7               A0          D7
 D0 | 9       16| D6               D0          D6
 D1 |10      15| D5               D1          D5
 D2 |11      14| D4               D2          D4
Vss |12      13| D3               Vss         D3
      +----------+                     +----------+

[Zucca]

Very happy to find such a post here.

Yes I´m on board too, I made yesterday a jump in the dark by buying this puppy:

http://www.ebay.com/itm/HP-5335A-Frequency-Counter-/181420545057?nma=true&si=q%252B7%252BHm8nU5AXQNl3C3Cf3Ut7vl4%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

Seller had 0% review in ebay....  When I will open this up I am worried to find dead animals inside. My be it was used by EE terrorists in the past. Keep you posted.

Can´t wait to tune it up...

Sorry for the slightly out of topic question... but which EEPROM reader to you suggest? I am missing such a device on my bench.

PS: I got water in my mouth for a rubudium 10MHz bomb now.

[orin]

My unit also has a Papst DC fan, its rated for 18 Volts, but it runs from 24 Volts !

Strange that official diagrams do not include this change. For sure it was build by HP like this.

I could change it for a Sunon Maglev, that should kill the noise 

This change from 110V to 24V is described in words, but I'm lacking the schematics.
So it was an official change, definitely.

The fan operates from 18 to 28V.

Replying to an out of date post, but since I just replaced my fan and fixed another problem:

The change was described in a service note (attached).

I strongly recommend replacing the relay socket and implementing the wiring change in the service note or one day, you'll turn it on, the fan will run, but you will get no display.  The relay socket is part #27E213, PB806-ND from Digi-Key.  The socket contacts fatigue from running too hot/heat cycling and eventually, when cool, the contacts for the 5V supply don't make contact any more.  In my case, I got strange behavior for while before it finally wouldn't turn on.

I have put an 8414NGM in my unit too, but be aware that it cannot handle the same static pressure that the 8124G can.  Compare the charts:

http://elcodis.com/parts/452608/8124G.html#datasheet
http://img.ebmpapst.com/products/datasheets/DC-axial-fan-8414NGM-ENG.pdf

I have no idea what is required in terms of static pressure vs. air flow for the 5335A.  All I know is that the original parts list specified 32CFM air flow for the 120V fan.

[1980s_john]

I got mine 5335a very cheap, because it was totally dead, but cosmetic very good condition

After lot of research, all of the tantal C's on the input board were totally short circuit. The blue bulbs in the picture.
The power supply is short protected, so replaced all tantals, and the unit was up and running, and in good condition.

Thanks for the tip, my 5335A is similarly dead (well the fan comes on and that's it), all the main PSU outputs read close to 0V with the regulator inputs are at +/- 12V and +/- 24V. I am used to shorted tants in IBM PCs, where due to the high current available the results are a little more spectacular 

Regards,
John

[orin]

I got mine 5335a very cheap, because it was totally dead, but cosmetic very good condition

After lot of research, all of the tantal C's on the input board were totally short circuit. The blue bulbs in the picture.
The power supply is short protected, so replaced all tantals, and the unit was up and running, and in good condition.

Thanks for the tip, my 5335A is similarly dead (well the fan comes on and that's it), all the main PSU outputs read close to 0V with the regulator inputs are at +/- 12V and +/- 24V. I am used to shorted tants in IBM PCs, where due to the high current available the results are a little more spectacular 

Regards,
John

If you have the DC fan, it's likely that the contacts on the relay socket have opened up.  See the service note in my post above.  The relay socket is a 27E213, Digikey part number PB806-ND.  If it is the relay socket and you do the modification in the service note, you probably don't need a new relay; I'm still using my original relay.  Anyone with a 5335A should make sure that this modification is done and switch to a DC fan.  The 5V supply relay socket contacts get hot, fatigue and eventually, when they cool down, don't make contact with the relay any more.

You can check if it's the relay socket by following the input for the 5V supply from the fuse and across the relay.  If the 5V supply is down, the other supplies don't come up either.  You might try reseating the relay (carefully, the top tends to come off the relay).  That worked for me for a while.

The relay itself is pretty much unobtainium - it's a 6PST NO with 5A rated contacts.  It should easily carry the 2A or so that I measured on the 5V supply, but the socket contacts don't.  The modification uses the contacts that were originally used for the AC fan in parallel with the original contacts for the 5V supply so the DC fan modification is absolutely required.

There is a similar relay available with 2A contacts.  I have one but haven't tried it yet.  I'm sticking with the original relay while it's working.

Orin.

[1980s_john]

After lot of research, all of the tantal C's on the input board were totally short circuit. The blue bulbs in the picture.
The power supply is short protected, so replaced all tantals, and the unit was up and running, and in good condition.

Thanks for the tip, my 5335A is similarly dead (well the fan comes on and that's it), all the main PSU outputs read close to 0V with the regulator inputs are at +/- 12V and +/- 24V.

I finally got around to working on my 5335A, the service manual is a must have. The input board is the 'A3 Amplifier Buffer assembly (05335-60003)', I replaced the big blue tant caps (22uF) with new 35V parts. It now powers up and the front panel / processor / display appear to work, but it is not working as the PSU voltages are still not right. I get:

-15V output = +0.7V
+5V = 5.07V
+10V=10.0V
+15V=15.7V
-5.2V=+0.6V
+3V=3.0V

So problems with the -15V and -5.2V rails, which appear to be independent. Any tips please?

Regards,
John

[1980s_john]

If you have the DC fan, it's likely that the contacts on the relay socket have opened up.  See the service note in my post above.  The relay socket is a 27E213, Digikey part number PB806-ND.  If it is the relay socket and you do the modification in the service note, you probably don't need a new relay; I'm still using my original relay.  Anyone with a 5335A should make sure that this modification is done and switch to a DC fan.  The 5V supply relay socket contacts get hot, fatigue and eventually, when they cool down, don't make contact with the relay any more.

Thanks, my relay seems to be OK. However removing it shows a black heat mark on the socket, presumably where the 5V passes through. Thanks for the service note, I must give it a go.

The HP part for the relay is 0490-1172. Printed on the side is the code R10A-E1-X6-V430, and a date code 7923. ebay shows loads of R10-E1-X6-V430, is the R10 2A relay and the R10A 5A then?

Regards,
John