HP 3458A - Fails Slave Test - Convergence

[Ade911]

Hello Frank,

Sorry I should have shared more testing results.
A3 Board

U230 20M oscillator OK, U131 OK , signal CK10 OK [ Not a square wave but still a clock pulse] .

U211 , 212 change state during reset or changing front panel buttons, not sure if they have anything to do with how U210 functions.

Unplugged P2 and P1 from the AC board to see if anything was affecting the signal DCCK_F [sitting at 5V]

Where can I find the pin configuration of U210, I tried google but failed, guess Pin 11 U220 is acceptable - no clock , sitting at + 5V. U220 Pin 19 has a +5V clock pulse [more like a saw tooth]

Good catch Frank, still learning from the master.

Is this signal generated in U210 or U220 ?

Tx Ade.

Pin configuration of U210???
It's on sheet 1 / 2of A3. What do you expect more?
It's a hp programmed Gate Array, in my 3458A it's an ORBIT 6968A, don't know anything about this device.
I have not measured inside my 3458A, but maybe the clock Pin 31 for the SR chain is only output, when needed. (*) Please scope on that pin, while you RESET the instrument, if there is an initial activity.
What about pin 73, now? Is there a clock, or not?
The 3458A currently does not work at all, anymore?

Frank

(*) That might be reasonable, so not to disturb the analog part by RF emission, during sampling.

Hello Frank,

I have the schematic , but when you said scope on pin 73 of U210 i was not sure where pin 73 is. I tried last night on paper to draw each pin and work out after Pin 1 where pin 2,3 and so on was but it made no sense so looked for the basic pins you mentioned connected to DCSTB_F, DCDA_F, DCCK_F.

Pin 73 U210 - Pin 11 U220 , checking on Pin 11 U220 - power on goes high, goes low just before a failure of hardware Beep. Replicate by resetting the front panel , goes low just for a ms or so.

Same error, as before;

202 Hardware- slave test convergence
110 Calibration Required - SCAL

Now checking to see why U220 voltage is not smooth on the chip pins but on the supply its smooth.

[Ade911]

Hello Frank,

Sorry I should have shared more testing results.
A3 Board

U230 20M oscillator OK, U131 OK , signal CK10 OK [ Not a square wave but still a clock pulse] .

U211 , 212 change state during reset or changing front panel buttons, not sure if they have anything to do with how U210 functions.

Unplugged P2 and P1 from the AC board to see if anything was affecting the signal DCCK_F [sitting at 5V]

Where can I find the pin configuration of U210, I tried google but failed, guess Pin 11 U220 is acceptable - no clock , sitting at + 5V. U220 Pin 19 has a +5V clock pulse [more like a saw tooth]

Good catch Frank, still learning from the master.

Is this signal generated in U210 or U220 ?

Tx Ade.

Pin configuration of U210???
It's on sheet 1 / 2of A3. What do you expect more?
It's a hp programmed Gate Array, in my 3458A it's an ORBIT 6968A, don't know anything about this device.
I have not measured inside my 3458A, but maybe the clock Pin 31 for the SR chain is only output, when needed. (*) Please scope on that pin, while you RESET the instrument, if there is an initial activity.
What about pin 73, now? Is there a clock, or not?
The 3458A currently does not work at all, anymore?

Frank

(*) That might be reasonable, so not to disturb the analog part by RF emission, during sampling.

Hello Frank,

I have the schematic , but when you said scope on pin 73 of U210 i was not sure where pin 73 is. I tried last night on paper to draw each pin and work out after Pin 1 where pin 2,3 and so on was but it made no sense so looked for the basic pins you mentioned connected to DCSTB_F, DCDA_F, DCCK_F.

Pin 73 U210 - Pin 11 U220 , checking on Pin 11 U220 - power on goes high, goes low just before a failure of hardware Beep. Replicate by resetting the front panel , goes low just for a ms or so.

Same error, as before;

202 Hardware- slave test convergence
110 Calibration Required - SCAL

Now checking to see why U220 voltage is not smooth on the chip pins but on the supply its smooth.

Hi Frank,

I cant see anything else it can now be that the A3 board, I thought about trying to replace the 8051 but I dont know if the signal is generated in this device or U210. I did see some pulses but these could be a trigger issue on the scope as its not constant.

Any other thoughts

Many thanks,

[Ade911]

Update sorry for the delay ...

With Franks great support and advise we narrowed the problem down to the A3 board - U220 and U210. Unfortunately I have lost my clock pulse which drives all the shift registers from U210. You may see a pulse upon power up but then goes high.

I also found that pin 20/40 U220 are not smooth, the supply has a ripple [see attached images].

Question, anyone seen this issue before , I've never experienced this on a processor but maybe its normal and hence the two inductors in series with the supply lines which are smooooooth.

I also wonder if this is at fault, can U220 be exchanged and does anyone have a copy of the internal software I could have please.

Thoughts ?

[CalibrationGuy]

I know this thread is old, but I'm curious to know if you ever fixed this meter after all the input from the people on the forum, especially Dr. Frank.

TomG.

[Ade911]

Hello CalibrationGuy,

Sorry for the delayed response, the 3458A was put to the back of the pile whilst I repaired two Datrons which are now calibrated and running well.

The answer is no, in fact I powered it up yesterday to see what was happening but still no sample signal.

Dr Frank is an amazing guy as well as some of the others who supported me , these people really know there stuff but I think I need a new A3 board  :'(

Tx ade...