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HP 8116A More Help Needed

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Mick B:
Hello all, I was given this HP 8116A w/001 option and it has an issue. When turned on the led's and display all come on like always, but they never go out? There are no stuck keys- when holding down a key the stuck key error is displayed "0". It looks like the first segment on the display is brighter than the rest looks like a 1? I am also missing both 24v rails unplugging all the other boards & lifting the +0Ω W15 resister still no voltage, Lifting -0Ω W16 resister I have both 24v rails. Getting to the op-amp to test is going to be a bitch I could get to the pins from the bottom, but I like that idea less. Has anyone seen this problem before? maybe save me some time maybe the chip U30 is not doing a reset? and the other boards need to be in circuit. I have been up hours reading and tracing schematics I'm starting to see double. I'm feeling a little :box:

Mick B:
Good morning, Update, all boards installed. Went through the troubleshooter for 24v rails and on to 10.4 the Shaper and Output Amplifier. As always it starts with clearing the error code by pushing the LCL key all this does is display the stuck key error "o". The reset pin on U30 is at 5v grounding it for a moment does nothing. Checking the voltage at CR501 &2. it's not a full +/_ 15v. OK!  NEXT step set it up for XXX and check the output????
I need to just STOP. .... OK regrouping.
1. Yes, I have no 24v rails, (A problem on the -24 rail).
2. But it seems, I need to find out why it's not completing the self-test first. or is it?
3. I can't find the information to diagnose this.
4. Is it in the manual and I'm missing it?
5. Is this what it looks like when the RAM, (which is the next step in the boot process fails?
 Can I please get some help? I know there are many experienced HP warriors familiar with the 8116A in this group. I want to keep this. I really don't want to see this on E-Bay, Parts only.

precaud:
I'd correct the power supply issues first, then check ALL of the 'lytics, especially down in the output stage. These things run very hot.

Mick B:
Yes, VERY, VERY HOT! it's a wonder they last so long. I started on the power supply first, whatever is drawing to much current is on the main board A1 I checked all the electrolytics and as time permits, I'm working on the tantalums. And the current sense resistors and the driver transistors are OK. Got to start somewhere as there are just to many components on the main board and unfortunately, it's not a dead short so I can't inject a little current and then use my thermal camera. Oh ya I also pulled U200 A 24v op-amp. There are 13 or so 24v transistors in the output amp section that could be leaking and not to mention, a few diodes. WHAT A TIME SUCK!  :scared:
Thats why I wanted to try the display problem because it lights up without the 24v rails. I can stop the Op-amp from doing a reset and perhaps then it will throw a code. but with the display all lit up I'll never know. GOD help me!
I also pulled the 3 HP chips

Mick B:
WTF?  :-//  417 people read this and no response as to the problem of all the display LEDs on. Come on guys, is it because the enthusiasm for something this old has come and gone? or maybe the more seasoned Techs (hobbyist) have left the group? I'm just trying to learn. This forum uses to be the GOLD Standard for information on electronics. I'll give it a few more days before I stop :horse: and visit fleabay. and another piece of classic HP goodness slips through my hands  :( and i will just have to keep using my Juntek8090.

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