HP 8565E Failure

[Patest]

I have an HP 8565E that will not power on, it starts to, the led turns green but then it shuts off and restarts repeating the cycle of events.
Any ideas on the problem?
Thank you in advance
Al

[Wallace Gasiewicz]

Do you have the manual or schematics?If you don't Artek has them
http://artekmanuals.com/manuals/hp-manuals/
Some of the Hp units have voltage sensors on the outputs of the PS that go to different boards, 
 If the drain is too high the PS shuts off.

[Patest]

I have a manual on order. My main reason for asking is to determine, basically, how big of a job the repair will be. The inside of these units are extremely dense and anything to with internal is usually an all day job.

[xmo]

Here is part of the service manual related to the power supply.

[xmo]

This is a superb instrument - well worth the effort to repair - although it may take you some time.  Still, I'd rather have this situation than one of those 3XX errors or a blown mixer.

Start by removing the unit from its housing.  Then disassemble it and inspect each module closely for bulging capacitors, leaking capacitors, burned components, or any visible fault.

If everything is pristine, report back and we will go to the next level.

[Patest]

  :-+Awesome, thank you

[dietert1]

We have a similar 8560 analyzer and i remember fixing the power supply some years ago. They have electrolytical caps for voltage doublers and there are some diodes missing to protect the caps from reverse voltage during power-up. Those caps failed while the others were still OK. Anyway it may be a good idea to recap the power supply. Tedious work though since the power supply is deeply buried inside and some of the caps have an extra shield.

Regards, Dieter

[Patest]

I have 2 of these units, the first one I repaired was easy, someone had terminated the lo with the wrong value, around 300 ohms if I recall correctly. It still has a thermal problem, shuts down after running for a while, it is the silicone heat sink compound on the microprocessor heat sink, when it gets old it turns to a powder and does not work as well, I will attempt to repair both units at the same time taking lots of photos, the interior as you stated is extremely dense.
I plan on attempting this when my work schedule allows me some bench time.
I am grateful for all the tips and assistance. This is a great site.

[djsb]

I recapped my HP8563E a while ago and also removed the CRT (which was the original problem) with a Newscope6 LCD. The recap cost around £50 for parts (bought enough for 2 instruments). The plug in SIMM style regulator board was loose in its socket and when it was reseated properly it all fired up. I remember reading in the Artek manual about the continuous rebooting problem. The manual is VERY thorough and will take you through all the steps needed to diagnose and solve what's wrong (test points, waveform sketches, table etc). One problem I came across was the layouts and the schematics in the service manual were different from the ACTUAL hardware. This is because the instruments go through several revisions during their lifetime.  It's this orientation that takes a lot of time to make sure you understand where you are and what you're doing. Once you develop this understanding, the actual work is fairly straightforward. The power supply PCB itself is quite robust, but it's multi layer, so you need plenty of solder wick and flux and a good desoldering iron. Another thing is it's awkward trying to get all the PCB and cables back into the case afterwards, so keep a note of the cable layouts. I did a post on this on here if you do a search, and I have a crude (as in unpolished as I'm a beginner at YouTube stuff) video up on Youtube of the LCD work I did (DJSBee)