Author Topic: HP 3582A Repair  (Read 668 times)

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Offline Duce67us

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HP 3582A Repair
« on: November 21, 2019, 04:20:20 pm »
Hi all - first post to the forum. Might as well dive in the deep end!
I picked up a unresponsive unit locally from a recent widower.  She said it worked in the past.  It looked pretty dirty, but I brought the unit home and downloaded the service manual.   
Initially the unit didn’t do much, except run the cooling fan, and create a single spot on the screen. 
Checking voltages revealed no +5.1vdc in the power supply.  Pulled the card - found and replaced a blown fuse.  Checked for shorted regulator(s) and ran into a number of bad filter caps in the power supply.  Now the power supplies are all happy, and back in spec. 

I have a screen!  Yay! But it is full of garbage - and the front panel seems unresponsive.  Boo!!!
I will attach some pictures 

The Display test is Good! 
However, further testing is pointing to The Processor Group. 
 So I have stripped the unit to the bare bones and have started Signature Analyzing !
Bought a Tek 308 to assist in the process, and Made some extender cards.

I am sure I will have more questions. 
« Last Edit: November 21, 2019, 04:54:12 pm by Duce67us »
 

Offline Duce67us

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Re: HP 3582A Repair
« Reply #1 on: November 22, 2019, 03:24:43 am »
Sometime While I was pulling the cards out of the cage, I decided that it might be a good idea to clean all the years of dust out of the motherboard connectors, and inspect the solder joints attaching all the edge connectors.  Pretty sure that I located more than one cracked solder joint. 

I also pulled the front panel, after reading that stuck or broken switches can cause the instrument to hang,  to clean and verify all the switches.  Needed to use deoxit on more than a few to get them working satisfactory.  I neglected to check the RPG before putting the front panel back together, and I will probably regret that later.   


 

Online Dacke

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Re: HP 3582A Repair
« Reply #2 on: November 23, 2019, 05:30:34 pm »
Seeing those cracked solder joints now makes me want to check my 3582A for the same.  Mine is perfectly functional,  but at least now I know that this is a potential failure point.  If you need me to look at anything on mine or need pictures of an area,  let me know.  If repairing the solder joints doesn't fix the issue,  the service manual states the first step to general trouble shooting is to swap the A1 input boards since they are the same,  and this can isolate a lot of other potential issues.  Not sure if you have tried that.

 
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Offline Duce67us

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Re: HP 3582A Repair
« Reply #3 on: November 24, 2019, 02:59:28 am »
Thanks for the input Dacke!
I figured as long as I am going to try and get this 3582A back in service, I sure need to check everything out during the process.  At one point, I pulled all the cards and swapped both A1 boards, also tried them in one position, A and B by themselves.   No real change. 

Another issue that I had to deal with was with the heat sinks on the A5 card.  The rubber grommets were all flattened and allowed the heat sinks to touch the board.  There is also some foam tape that had collapsed that was supposed to keep the 40 pin ic in their sockets.  You might notice there is a grommet that looks pretty good, not flat like the others. Because the screw on that side wasn’t installed correctly.

Right now I am knee deep in learning to use the Signature Analysis. 
The good news is, the processor is not dead.  My A7 board passes the primitive test, and has the correct signatures on the IDA Bus. 

Tonight I did some SA work on the A9 display board.  Trying to get the display to a readable screen. 
I located some typographical errors in the service manual in Table 8-5-1 Display Controller Signature Analysis
Down in the Signatures for SA Test #1.
U3 pin 1 should be 7AC3, also U5 pin 10 should be HFU6.




 
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Online Dacke

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Re: HP 3582A Repair
« Reply #4 on: November 24, 2019, 10:04:16 pm »
Great.  I hope you keep updating your progress.  I've never done signature analysis or used any data analyzers before so this will be interesting for me to follow.
 

Offline Duce67us

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Re: HP 3582A Repair
« Reply #5 on: November 28, 2019, 03:39:37 am »
I guess I should say that I also have never done signature analysis before, or used any logic analyzer.  Just the schematic, maybe a pinout/data sheet and a 'scope. 

anyway, the real fun begins, exploring the circuits, and the idea of having a new tool to assist in the process is refreshing. 
So we begin at the Basic Processor test loop - Just the A7, A9 and A10 boards in the card nest. Follow the setup for the SA and probe +5v. and get 9PA2
Great! Now we check the IDA Bus signatures, and they match exactly the table provided in the service manual.
Now move to the Primitive ROM test.   
The manual states that to enter the primitive ROM test, install A6 board (ROM), move jumper A7 (J2) to run and power on, then short out A7(J4) and press RESET on the front panel - Keep A4 shorted.   +5v signature = OH62  should appear in about 10 seconds. 
My board did not ever give a signature.  But that is OK, because there is a pretty extensive ROM SA listing that covers address, chip select, and Data lines. 

« Last Edit: December 04, 2019, 02:56:22 am by Duce67us »
 

Online Dacke

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Re: HP 3582A Repair
« Reply #6 on: November 29, 2019, 06:46:53 pm »
You stated that you replaced some (all?) of the caps in the power supply.  About half of the caps there are axial lead,  and I'm kind of forced to use axial as replacements because the power supply is so cramped for space with the boards stacked so closely together.  Since axials are so much more expensive than radial,  did you use axials and where did you get yours?  Digikey has a very limited selection of mostly general purpose, 85C rated 2000 hour caps so I've been looking around at pricing.
 

Offline Duce67us

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Re: HP 3582A Repair
« Reply #7 on: November 30, 2019, 03:12:41 am »
Yes,
I priced the axial caps too.  I usually go to Mouser and get a price comparison, then decide if the cost is worth the extra.   In the end, for this unit, I just used what I had on hand, and converted radial over to axial by adding solid wire and heat shrink.  Mostly the 470uf caps were bad through out the boards.  These were the three legged ones, two at the bottom were active.  I just used some gray 3m 4991 VHB double sided tape to help hold the new caps to the boards.   

I hope to poke around a bit more in a few days, and post more results. 
 

Offline Duce67us

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Re: HP 3582A Repair
« Reply #8 on: December 04, 2019, 03:40:21 am »
The ROM board SA process doesn't have explicit instructions for setup.  It doesn't help matters that the manual has a picture of the A6 board with the SA header incorrectly labeled as J1.  When I set my CLk, Start and Stop lines to rising, my ROM board had the correct signatures for all the address bus, select addresses, chip selects, and STROMS.  When checking the overall data, everything matched except LS Byte #6 line.  The manual gives the signature C1AC, my reading was C1A0.  Manual says once found, simply move the start/stop lines to isolate the misbehaving ROM. 

GREAT! Except, the page is cut off for the signatures on the U3,4, 11 and 12 test. 
Also, the only way that I could pull in the correct +5 signature was to transpose the rise/fall setting for the start and stop lines. Once I used my own settings, all the  ROM signatures that I had information for  matched.   If anyone with experience or firsthand  knowledge could help interpret this result, I would be grateful. 
I need the LS Byte signatures for #6 data line.  There are 4 signatures I would love to have.  The +5 sig when Start/Stop is at TP4( mine was 826P), the +5 sig when start/stop is set at Tp2 and tp4 (7A07)
The LS Byte signature I got was 3306 for (TP4 only) and A7PF for TP2 and TP4.

More to follow
 


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