Hello Kevin
Thanks for your reply.? I have been away for a few days of vacation and only getting to my email now.
My unit does have the HPIB option installed.? I took a look at the board and it is wedged in between the back of the case and the crystal oscillator.? I am not sure how to remove it, without removing the CO.? I will give the service manual a closer review to see how to do this.
I have tried to do the error checks but the unit does not respond, only the keyboard check seems to work and all the keys appear to be functioning.
I found in the service manual that a 1 on the display indicates that the A14U7 ROM is bad.? HP gives a part number for this as 1818-0706.? I think this ROM chip is now unavailable.? I could not locate it on the microprocessor board.? All chips are 1820.? Sounds like it may be toast for this unit.
Terry
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On 7/11/2019 6:38 PM, Kevin Oconnor wrote:
Terry,
What options does your unit have? There were a lot available. Possibly one option is hanging the control processor. Do you have the HPIB? It can hang the processor. As option 11 I think you can remove it. It¡¯s a process of elimination. These counters are a bit older than the later reciprocal counters with more powerful single chip solutions. So
debugging might be significantly different.
This counter has some self check features and error messages. What do these report?
I it reports you have a starting point. If you can¡¯t get any response after the PO test, you will likely have to look at the internal microprocessor bus. You indicated that the display does some PO check, which to me says the micro is not dead but hung or waiting for something. You may also have a bad ROM(s).
The manual explains how the systems work, must it is not for the faint of heart!
Kevin
