Author Topic: HP 3561A repair  (Read 1327 times)

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Online FloopyTopic starter

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HP 3561A repair
« on: October 21, 2018, 01:36:37 am »
Hello,
I recently acquired a HP 3651A. When I first got it, it didn't want to turn on. After some troubleshooting I replaced a diode package in the power supply (picture attached). It seems to work, but unfortunately the screen is compressed. What could be causing this? Anybody is more familiar with CRT drivers than me. I'm at least 95% sure that the digital display driver is working properly. Anyway probing around, the fast sweep synchronizer signal seems to be what it should be (FSYNC)(The service manual has pictures). The only anomaly I have seen is the LowPdrive (pulse drive) and FSYNC seem to be a little bit out of alignment. (see picture) Usually they are supposed to be aligned
If anybody is interested in what I'm saying, have a look at the service manual.

(Start at page 214 for the analogue display)

http://www.ko4bb.com/manuals/174.148.87.57/HP_3561A_dynamic_signal_analyzer_service_manual_V2_1983.pdf

If you don't care at least I have some photos! Very nicely built that's for sure!
« Last Edit: October 21, 2018, 01:41:09 am by Floopy »
 

Online FloopyTopic starter

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Re: HP 3561A repair
« Reply #1 on: October 21, 2018, 01:38:08 am »
The rest of the pictures
 

Offline SilverSolder

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Re: HP 3561A repair
« Reply #2 on: October 21, 2018, 04:39:07 am »
The distorted picture indicates a problem with vertical deflection called "vertical foldolver".

Check the output stage that drives the vertical deflection coil - bad solder joints, capacitor deterioration, resistor drift, bad driver IC, etc.

Check out https://www.repairfaq.org/samnew/tvfaq/tvvfold.htm

and https://www.repairfaq.org/samnew/tvfaq/tvcovertp.htm

...and other vertical deflection articles on that site which look relevant to this repair.

 

Online FloopyTopic starter

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Re: HP 3561A repair
« Reply #3 on: October 21, 2018, 04:34:58 pm »
Thank you I needed guidance.
 


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