Gould 1604 waveform processor

[Electrical]

Hello Simon/Dazzelvision, I can confirm that the 160A and 260 keypads both use the same PCB assembly. I took the 160A keypad apart and I found that the PCB assembly has all 51 buttons fitted and that only the button template is different, and that the same key has different functions depending which waveform pod is fitted.
For example on the S5 on the 160A keypad is the “Capture” button and returns 96 on test, S5 on the, 260 keypad is the “Initialise Restore” button and also returns 96 on test. If you convert 96 to binary and put it in least significant bit first order it gives 00000110 which corresponds to X0Y5 in the truth table for the standard form of encoder chip. So the software in the 160A and 260 waveform processors must decode the different functions for these keys.
I have attached some pictures of the keyboard and a scan of the 260, keypad layout and a list of the tests results from both the 160A and 260 keypad tests.
Simon I wonder if you fitted the 260 EPROM in the 160 processor, if it would up grade to a 260, then you could write a test routine using a keypad instead of a computer. Also there are differences in the matrix between the older 160/170 keypad and the 160A/260 keypad and my test results do not tally with the results in your Function Matrix list for the cross points in the matrix.

Regards Stan.

[scirturbo]

Stan,

I compared your test results of the 160A with my findings and see no differences. I only made one little mistake, I reversed the "capture" and "capture&repeat" function. Other then that all the numbers match.
I also did a keypad test after you explained how to do this, and they also match the coding table. Could you explain what numbers don't match?

I got a eprom dump of a 260 from Phil but it didn't work. He also added a checksum of the dump but it doesn't match with the dump that my programmer puts out. Maybe a corrupted file...
I'm planning ( I already have a prototyp running) to program a microcontroller which reads a keypad, decode the key and send the code with 600baud to the pod. It would also be possible to write code that will translate 160a keypad code to a 260 keypad code.
I'll ask Phil if he could do a new read of the 260 eprom which will match the checksum, it should work acc to the compatible table with my rev.

Simon

[Electrical]

Sorry Simon I think I have been comparing my list with the one for the 170, the only matrix points that are different on the 160A list are the Capture and Capture and Repeat. The S numbers are from the rear of the PCB board. I tried the keypad out on the scope without the 160A button template and using the picture of the, 260 keypad I tested all the functions and they all worked, so the waveform processor is OK. The reason the 160A keypad does not work is the buttons are not in the correct place, e.g. the function key F is S20 with the 160A button template and is S11 with the 260, so pressing F on the 160A keypad gets menu1, which is the same as pressing 1 with the 260 keypad.
Sorry for the confusion and regards Stan.

[dazzlevision]

Hello Stan,

The Gould 260 booklet simply lists the keypad encoder IC as a KR9602 (Gould part number 456219).

I will open up the keypad and see how the actual device is marked.

Regards,

Dazzlevision

[scirturbo]

Stan,

I understand you have a 260 pod and a 160A keypad? If so then it would be possible to exhange the eprom of the 260 pod for a eprom of a 160a. Then your keypad should work correctly. I can burn you a copy of my 160a eprom and send it to you, free of charge..

Simon

[Electrical]

Hello Dazzelvision, I have opened up a 160A keypad and I found it is the same as the 260, all 51 buttons are on the PCB inside and only the button template differs between the two types, so there is no need for you to open up your keypad. Manny thanks for the offer.

Simon I do have a 260 pod, but the keypad I was using is on loan and I will have to return it, so if I find either type of keypad I know it will work with my scope. Thanks for the offer to make a copy of the 160A EPROM but I am sure I can get a copy of it locally if and when I need it. It is very good of you to offer to do it for me. I could try and get a copy of my 260 EPROM if you would like to try up grading yours.

Regards Stan.

[dazzlevision]

Hello Stan,

I have found that, if I remove the 260 waveform processor pod, I can then set the date and time on my scope. However, if I power down the scope, this is lost and it has to be reset.

Now page 31 in the 1600 user manual states that the date & time setting is battery backed. However, looking into the scope, I can see no back-up battery, unless it's in one of those hybrid data and time ICs with an integral battery.

Would you be kind enough to have a look in your Gould 1600 service manual, to see how the date & time is managed/battery backed, please?

Many thanks,

Dazzlevision

[Electrical]

Hello Dazzelvision,
When I remove the 260 pod from the back of my scope and set the time using the menu it losses the time when I switch off and has to be reset when I switch on. The battery backup for the real time clock is inside the 260 pod and I think you have already told me that you have changed this battery. However the real time clock chip may have been corrupted when you replaced the battery, the only way to reset the real time clock is to remove link L1 and wait a short while for the capacitors to discharge and replace the link. This should rest the clock.
You may have to put a voltmeter across the supply pins to the chips to ensure all the voltage across the capacitors has been discharged.
I hope this helps regards Stan.

[dazzlevision]

Hello Stan,

I will try what you suggest.

It looks like a misprint then, in the Gould 1600 series user manual, as it definately refers to "battery backed" (and not with a rear "pod" fitted).

Regards,

Dazzlevision

[Electrical]

Hello Dazzelvision, I have just been reading through my rather old copy of the user manual and in section 2 it refers to the menu and set up of the instrument can be saved to any of four battery, backed memories, which can be recalled after power down. However in one of the amendment sheets it states that these memories are non volatile and the only way to reset a corrupt memory is to do a system reset by holding the plot and trace hold buttons and powering up. This will erase the memories and a new set up can be stored. I have looked at the service manual but it only refers to the battery B1 in the 160A/260 waveform processor pod. The only thing I can think of is the early versions of the 1600 series used a battery backed memory and the later versions used non-volatile memory, I cannot find any other batteries in my scope unless it is under the main board.
As a matter of interest there was an additional memory module, which could be attached to the back of the scope and this may have had a battery in it, but I do not have any information on the module, even though all the scopes at work had them fitted.
Regards Stan.

[scirturbo]

I can confirm that my 1604 has a NiCd battery just under the ch 3&4's extension board. It's also on the schematic of the cpu diagram page 84. It holds power to the Ram memory U3 and U19 which has a line connected to it called RTC which goes to the pods timer ic CS pin.

Simon

[Electrical]

Hello Simon, you are right, but I think that battery is only for the system set up, settings. Without a pod with the real time clock in, the time and date will be lost as the CPU must be doing the job of the clock using it’s own timing clock and dividing it down and on power down the clock function will stop. U19 is a 74HC123 dual monostable and must send or switch the timing data from the real time clock or the CPU, the monostable is battery backed, but as a guess I can not see why they would use two real time clocks and put one in an optional pod.
Again sorry for the confusion, my only excuse is my eyesight is very poor and I keep putting off the operations, I will have to get a bigger magnifying glass.
Regards Stan.

[scirturbo]

I could try and get a copy of my 260 EPROM if you would like to try up grading yours.

If it's not too much trouble then I'd really appreciate this. If it is then that's fine too. You (and others) are really helpful with all the info that you have published and I now have some nice extra features on my scope!

Have to buy some buttons now.

Simon

[dazzlevision]

Hello Stan,

I have found the NiCd battery on the 1624's main board and it has been replaced recently (voltage OK). I agree that there isn't a RTC IC on the scopes main PCB.

I tried removing the memory pod's battery isolation link (LK1) but no change - I still cannot set the date & time with the pod connected. I'll try using another scope to see if there is any activity on the links from the scope itself to the pod's RTC IC. Failing that, I guess I'll try and locate a source of the RTC IC, which is probably long obsolete!

As an aside, I attach a scan of two pages from a Gould sales booklet for the 1600 series. It seems that the (205 memory) pod at the rear is fitted as standard on 1624s and gives enhanced memory for storage of traces. It only needs the 260 keypad in order to have the waveform processor features as well. It also refers to the Real Time Clock, under the "260 Waveform Processing" heading, so this seems to confirm the above (i.e. the non-volatile RTC feature is only available with the 205 memory pod fitted).

I would like to get my 1604 going and it looks like the power or scan/EHT boards are u/s. Would you be able to scan just the circuits for these and post here, please?

Regards,

Dazzlevision

[Electrical]

Hello Simon, I will try and get the loan off an EPROM programmer at the weekend. I will try and make an image of the ROM and send it electronically so you can compare with the image that Phil sent, if that does not work, I will get a blank 512 EPROM and copy the image and try it in my scope to see if it works before I send it. This may take a while so please bear with me and I will let you know how things are going.
Hello Dazzelvision, before you replace the real time clock chip you could try exchanging the positions of the pods on the back of the scope they will work in any position. With reference to the diagrams, please find attached PDF’s of the drawings and the servicing fault finding flow charts, which I think may be relevant. Have a look at the System Overview in post 16 and see if you need any more information.
Regards Stan

[dazzlevision]

Hello Stan.

Thanks very much for the scans. Could you also scan the main power supply circuit for me - the PCB mounted vertically on the r/h/s when looking from the front, please?

Many thanks,

Dazzlevision

[scirturbo]

Dazzle,

It's in the servicing pdf. My 1604 had some bad, dried up caps in the +12/-12v section. This caused a blurry image that slowly disappered when warming up. If you are going to take the p.s. out then you might as well replace those.

Simon

[dazzlevision]

Hello Simon & Stan,

Gould 1600 - main power supply board circuit diagram.

I obviously didn't look carefully enough in the servicing pdf!

Many thanks,

Dazzlevision

[dazzlevision]

Hello Stan,

I have now turned my attention to my "donor" 1604 scope which is virtually dead (no screen display, power and trigger level LEDs lit). The first thing I did was check on the NiCd battery on the main PCB, which was the original and leaky. Removing this, I see that the lead out wires of resistors R2, the resistor right next to R10 (illegible PCB silk screen here!), R24, R37 & R79 are corroded and have parted company with the main body of each resistor!

Can you look up their values in your service manual, please? They are all 0.125W types - very small, but at least they are not SMD types!

Many thanks,

Dazzlevision

[Electrical]

Hello Dazzelvision
Please find attached a JPEG file of the components list Section 6 for the Main Board 1604. As there are lots of pages of components will you please check that there is no prefix to the resistor numbers, as different sections of the main board have different prefixes? Perhaps you could check I have sent the correct page by checking the values of other components in the same area against the attached list to make sure the values correspond before you change the unknown resistors.
If you need any other parts of the component list please let me know.

Regards Stan.