View Single Post
Old 16th Nov 2011, 10:50 am   #1
John Engineer
Retired Dormant Member
 
Join Date: Nov 2011
Location: London, UK.
Posts: 6
Default Gould 1604 / 1624 Oscilloscope Problems

Hello
THIS POST IS TO HELP OTHERS WITH 1624 GOULD SCOPE

I own two Gould Oscilloscopes, 1604 & 1624
I use to work for Gould back in 1989 In the test & service department.

I have full services manuals & a full range of Eproms of different software revisions for the two scope's and the add on modules that plug on back of the scope. If anyone needs software updates I can send you eproms if you let me know what version you need.

Both of my scope's have developed strange faults over a period of time which puzzled me, the 1624 would not work with modules plugged into the back, no LED's on front panel, and no crt, thus the 4 channel Diff stopped working due to wave form module not working. If I removed both rear modules scope would
work, but seemed sluggish and I knew deep down there was problems. After digging out the service manuals and inspecting the main board, the first thing I noticed was the battery had leaked on to the pcb and was not reading a good voltage.

I removed the battery and ordered a replacement new battery, the design of these batteries are very poor because they are not sealed! and the acid erodes the pcb tracks on the main mother board. It has caused lots of damage to my pcb. I have chosen to take fly leads away from the pcb and place the new battery nowhere near the main motherboard and wrap the battery in insulating tape.

The same problem I found in the waveform processor module, tracks destroyed and acid leaking all over the pcb !! after replacing all the damaged tracks in both the waveform module pack and on the main mother board with very fine pcb wire. I still had the same problem whereby the scope would not power up ??

I needed to look closer at what was happening, so I started to probe around with a scope on the wave for pack and could see some very strange looking waveforms on the KROME & the scope main Processor E & Q pins. they were floating at about 2.5 volts with very strange waveforms on these pins. I knew they should be 5v data/chip select lines. All these bad signals were coming out the scope on the two rear module connectors.

So I started to cut pins on ic's on the main board and rewire the tracks one by one to each IC where I had isolated the pins from the main pcb for all given problem signals found. I also had to cut tracks going to the rear module connectors and rewire the tracks to the IC's. After creating lots of new tracks and what seemed like minor brain surgery, when looking at on these previous problem pins I had lost the 2.5 volt floating levels and could good looking 5v waveforms.

I also rewired many new tracks in the waveform processor around the battery plugged in the module and hey presto the 1624 scope was all back working again.

It turns out the battery leaking on the main board and in the waveform processor was causing the damaged tracks by battery acid to cross talk and induce strange levels between the pcb tracks. The only cure was to isolate these tracks to IC's and rewire the tracks.

I can stress how important it is to lift this battery of the main mother board, if you own a Gould 16xx Oscilloscope please add fly leads to this battery and get it away from the main motherboard and seal the battery. It will destroy your scope if you leave it on the board !

It's a little more harder to over come the very tight space in the wave form module, though Im thinking of having the battery out side the waveform module case on fly leads to prevent further damage.

So I was very pleased to have rebuilt and brought my 1624 back to life after a fault that had bugged me for a few years.

This took me quite a few hours and brain power to get to the bottom of what was wrong as there was multiple issues on the main motherboard and in the wave form module due to battery damage.

I hope this can help others who own the 16xx gould scope, this is a major design flaw with both gould and varta who make these horrible batteries.

There must be many other scopes out there with the same problems.

I have a very strange issue with my 1604 Scope, please see my 2nd post for full details.

If anyone can help me It will be very much appreciated,

Thank you
John Engineer is offline