Troubleshooting a HP 8664A Signal Generator with error code -8,010,311

[ARod12]

I have a 8664a Signal Generator with an error code -8,010,311 when the diagnostic test was performed. Accordiing to the service manual the error code means there is something wrong with the refrence. I have connected a counter to J1 of A9(refrence assembly) and has a 250MHz output. Then at J3 (ribbon cable) all the power supply voltages are fine. J4 and J5 seem to be working fine as they input 4KHz and 200KHz into the refrence assembly. However the last three connectors that have cables cables(W86, W88, W89) have no frequency coming in or out of them and those lead to the rear of the signal generator which I havent gotten the chance to inspect. Im thinking there might be a jumper that might be loose or the potentiometer to adjust the timebase is broken in the back of the generator because I connected my counter to the signal generators 10MHz out and nothing is coming out and then I connected the counters 10MHz output to the generators input and nothing displays on the screen to indicate external refrence. I would greatly apprechiate if anyone has info in this problem.

[Chris56000]

Hi!

Just a thought – there are four volumes of S.M. for the HP 8663a that go down to component level circuit and layout diagrams – have you downloaded these four volumes for the 8663a to see if there is any resemblance between the information given for the 8663 and the boards and modules you have in your 8664a?

I have found both HP and Tek used to release a full service manual with schematics for the first model design of a particular class of instrument, then followed up the service manuals with later model designs in the same class of instrument which only go to module or assembly level – and they do not advertise this in the documentation!

The way to find out if a manual is derived from an earlier model is to look at the small "figure reference numbers" given for each drawing – if a service manual has figures common to an earlier design a lot of the "figure reference numbers" will be alike between one manual and another – an example of this being the HP 1715A and 1725a oscilloscopes, which use a lot of common modules, and the drawings from Keysight's 1725A manual are clearer than those they've uploaded for the 1715A!

Chris Williams

[Moxon]

Hello,

Did you repair the -8,010,311 error code what did you find?  I have one with OPT. 001 with a similar same code (-8,010,310).  Also no signal on the rear panel 10MHz Ref. Out.

Have a replacement REFERENCE module on the way but now thinking the problem is elsewhere.

Any tips on how to disassemble for access the 10MHZ Reference Osc. (A20 location)?

Thanks

[lugaw]

Hello,

Did you repair the -8,010,311 error code what did you find?  I have one with OPT. 001 with a similar same code (-8,010,310).  Also no signal on the rear panel 10MHz Ref. Out.

Have a replacement REFERENCE module on the way but now thinking the problem is elsewhere.

Any tips on how to disassemble for access the 10MHZ Reference Osc. (A20 location)?

Thanks

The A20 is on back right side when facing the instrument.  Remove the bottom cover and you can force remove the A20 module just be careful there's lots of wires.  I was able to fix mine by removing the transistors that suppress the OCXO output and placing a jumper in place of the output diode.  My oscillator is still working and there was a problem with the auto sense system when there's another oscillator connected to A20 which the 8664A doesn't use.

If you don't want to remove it you can use an external 10Mhz source.