HP 1660A Logic Analyser schematics?

[Witchy]

Hi folks,

Turned my venerable HP1660A on today and the CRT is less than well. It's not quite vertically collapsing but the picture is wobbly and stretched at the top.



Service manual flowchart says 'check voltages and signals -> check cable -> replace CRT module'

I'm surprised that I can't find a schematic online. Does anyone know if one exists? Particularly for the CRT module which is made by Hitachi. I don't feel the need to replace ALL the caps, possibly just the ones in the vertical timing circuit. Apparently there's a bipolar cap that's difficult to replace with a modern equivalent but I've not looked too much at that yet. It's obvious which one it is on the board though, it's the only one cable tied in.

Voltages to the CRT board check out as per the service manual.

Any hints greatly accepted.

Cheers!

 

[Al Kossow]

I'm surprised that I can't find a schematic online. Does anyone know if one exists?

As I understand it, all of the internal documentation from the Colorado Springs operation were lost in a fire.
They never released schematics to users after the 1630, and it appears they don't even have it themselves,
I've asked.

Their name for the "good" documentation was the "Technical Documentation Package"

 

[daver2]

I have the 1650A and 1651A service manual, but (again) no schematics I am afraid.

Dave

 

[Witchy]

As I understand it, all of the internal documentation from the Colorado Springs operation were lost in a fire.
They never released schematics to users after the 1630, and it appears they don't even have it themselves,
I've asked.

Ah, that's a bit suboptimal. I hope no bodies were hurt in the fire and it was just paperwork. It looks like I might be blanket replacing the caps after all in that case.

Cheers,

 

[daver2]

Yes, it does look like a capacitor breaking down doesn't it...

Dave

 

[Witchy]

Took all the big and nearly-as-big caps off the other day and tested them with my Peak meter. Only one of them was below spec but the issue is still there after replacement, so I'll pull and test the rest of them at some point this weekend.

A