Repairing and Upgrading an old PM3320A - Including adding FFT!

[SaabFAN]

Well, it was sitting here in my room, waiting to be sold, looking at me, daunting: "You can't fix me!  " 
I can't have something like this.

Also a more accurate idea where the problem lies could fetch a better price on ebay, so I gave it one last shot. ^^

But now it's available on ebay again, because I had the opportunity to get another PM3320A (With FFT ) and I took it.
That one works. It's a little out of spec and needs adjustment, but nothing blew up in there and distributed the faint smell of magic smoke everywhere.

FFT is apparently only added via Software btw. The A10-Slot in the working unit is unpopulated.

[macboy]

...
FFT is apparently only added via Software btw. The A10-Slot in the working unit is unpopulated.

Interesting. Do you have an programmer to dump and compare the ROMs? I wonder if swapping ROMs from an FFT unit would be all that is necessary. It could also be as simple as a jumper on the PCB. CPU reads the state of an I/O pin or two and sets options accordingly.

[SaabFAN]

No, but I'm planning on buying one of these TL866 Universal programmer-thingies from China next month.
I can't read the programmable logic chips with those, but they basically can read and write 99% of all the available types of EPROMs.
Once I have it, I'll create som ROM-Dumps.

On the CPU-Board, there also are 5 Jumper. 4 are being used to set normal operation or testing-modes. The 5th one isn't explained in the Service Manual.

[dom0]

I can't read the programmable logic chips with those

Thinking about it only the software is missing but I never tried (yet) to create a new IC definition for it.

[SaabFAN]

What needs to be in the IC-Definition? Voltages, Position of I/O-Pins and Supply-Pins? Anything else?

Reading the programmable Logic Chips might be a bit difficult though, even if an IC-Definition exists and the TL866 can access the chip: The ICs have protection-fuses that prevent the readout of their program-memory if set. If Philips has set those fuses, the only way to get the content of the memory would be to try all possible combinations of inputs, keeping the internal registers in mind (Previous State and Next State) and record the output.

By the way: The Programmable logic ICs in both Oscilloscopes have been programmed with a program from 1987.
Seems like the programmable logic remained the same throughout the production-cycle and only the Software for the 68k-Processor was updated.

[dom0]

What needs to be in the IC-Definition? Voltages, Position of I/O-Pins and Supply-Pins? Anything else?

The software will also need some kind of protocol definition to know how to read or write bytes. If I were to write a programmer software I'd separate protocol and devices using them into separate entities, there is also an open source software for the TL866 around so you'll probably gain some insight there.

Regarding trying to reverse-engineer the PAL contents this should be possible with the TL866, too, since it's essentially just an I/O interface with some perks (programming voltage generator etc). But you'd probably need to roll your own software for that.

[SaabFAN]

I have now received the TL866CS and am about to open the Scope (the Okay one) again to get to the ROMs and download the images.

Question now: Where can I upload the ROM-Dumps? The scope is 25 years old, so the Software inside could probably considered as Abandonware, but I'm not sure if that is enough to put a zip-file here.

[dom0]

http://www.ko4bb.com/manuals/

[tautech]

http://www.ko4bb.com/manuals/

+1 

[SaabFAN]

I just uploaded the ROM-Binaries. They should be available shortly on KO4BB.com.

The Firmware-Version of these ROM-Files is 4.1 for both the Scope and the GPIB-Module.
The Chips are 27C010 on the GPIB-Module and 27010 on the Processor-Module. There are 2 EPROMs on the GPIB-Module and 4 on the CPU-Module.
I couldn't read the PLS-Chips and the GALs though; My Programmer is not advanced enough for that (a TL866CS).

From what I learned during the repairing-attempt, the FFT-Option is added via Software only. So programming any PM3320A with these binaries should add that functionality.

[tautech]

I just uploaded the ROM-Binaries. They should be available shortly on KO4BB.com.

From what I learned during the repairing-attempt, the FFT-Option is added via Software only. So programming any PM3320A with these binaries should add that functionality.

Do you think it is a FFT switch/option to be enabled from a "service" mode?
That is, options are all installed in software to be enabled in Service mode or with SPI commands as many scopes are. 

[SaabFAN]

I don't think so. There are only EPROMs on the boards as Non-Volatile Memory. And the Service-Manuals show no 12,5V Supply for programming the EPROMs or any other circuitry able to do that.
The only way to add FFT seems to be reprogramming the EPROMs.

[SaabFAN]

It should be possible by the way, to upgrade the earlier models to the later ones. The Service-Manuals show some differences, but the basic circuitry remained the same. It seems that all that is required to upgrade to the later versions is the addition of 2 ROMs (And all 4 ROMs programmed with the right software of course) on the CPU-Board and 2 RAM-Chips on the MRAM-Board.

[Stonewerk]

Hi! I'm new to the board, and I thought I'd report on the status of my firmware upgrade attempt (using the files uploaded to ko4bb by SaabFAN) and to seek assistance with an associated problem...

Firstly, my PM3320A is model PM3320A/80 - rack mount, with the GPIB/RS232 option installed - and was manufactured late 1988 (from IC & firmware date codes). The original firmware, as indicated by the service menu, is V02 G. v. 0s 88-05-18.

I successfully programmed and installed the 4 CPU ROMs, and the service menu now indicates f/w version FV4.1 L. v. 0s 89-05-09 with correct checksums for all 4 ROMs. So, at least initially, everything seemed fine.

However, when I traverse to the MATHEMATICS menu, the Histogram and Filter selections are there, but F.F.T. selection DOES NOT APPEAR. (I cannot recall if the histogram and filter selections were available with the old firmware, and I haven't reinstalled the original firmware to check.)

Other comments: The MRAM (A5) board is fully populated (HM62256 x 4), so I don't believe memory is the issue. Also,  I did not update the firmware on the GPIB/RS232 board, as I didn't think it's relevant.

I am hoping this is a user issue, and that I'm not using the menu correctly.

The following is an example of the procedure I am using to attempt to access the FFT function:
1. Apply scope CALibrate signal to Channel A.
2. Press AUTO Setting
3. Select CURSOR
4. Select MATHEMATICS
5. Select MORE

The HISTOGRAM and FILTER selections appear, but the FFT selection does not. (If I repeat the procedure with the signal applied to both A and B channels, the DELAY CHAN option appears, as expected).

What am I doing wrong?

[SaabFAN]

Have you checked the Checksums of the ROMs?
On my scope they are:
D1724:4CEC
D1726:A422
D1727:2961
D1728:F10F

Can you also check the PLS-Chips, or essentially any chip with a sticker on it and post pictures here? If they were evil at Philips, they programmed some kind of switch inside those chips that enables/disables the FFT-Function. But I doubt that.

[Stonewerk]

I did confirm that the ROM check sums match - the parts programmed  correctly, and the CPU ROM images that you uploaded  to ko4bb are 100% correct.

There are 2 PLDs on the A5 MRAM board; I'd expect that the labels on the 2 Signetics PLS105F devices are different from yours at least by merit of manufacturing date. I don't think that there's anything we can conclude from this, short of (not) being able to actually read the devices.

I agree that a PLD implemented feature "switch" would be evil, but then again, that would be characteristic of an "active" marketing organization, eh?    I do hope this is not the case....

Nevertheless, on the A6 CPU board, there are a number of jumpers - and unused jumper positions  - that merit comparison.

((( This is my second attempt at posting a reply. In my original reply, I had attached detailed images of the 2 PCBs, without noticing this forum's stringent file upload size restrictions. The 5 images were ~4000kb each.  I've reduced the images for upload, hopefully without losing detail...))))

[SaabFAN]

So far I can't see any difference between my Scope and yours. Apart from the warning-sticker (on my unit it is in english ). The jumpers on the board set several Debug/Test Modes and Turn On/Off the Watchdog-Timer.

The FFT-Function should appear at the second spot down from at the side of the screen.

Unfortunately I am currently busy with a University-Project, so I don't have the time to compare the stickers on the MRAM-Board, but I think they were also identical to yours.

The only thing I could think of now is the DPU and DCU-Boards (Units A8 and A9). Those two form a programmable DSP, which might be responsible for at least some of the calculations.
Did anyone else here try to upgrade a PM3320A to add FFT-Capability?

[SaabFAN]

CORRECTION!
I had the image of the PM3320 Service-Manual in my head and just looked over the schematics for the PM3320A again: There are 2 PCB-Jumper that seem to be located on the backside of the A6-Module. These 2 Jumpers decide how the 3 Lines UPAB17 - UPAB19 are are connected to the addess-decoder that controls the 2 lines SLRO0 and SLRO1 that connect to the Chip-Select lines of the SRAMs.
The Service Manual for the PM3320A even states: "If software releases with 64k x 8 ROMS are used, then the soldering joints J1701 and J1702 should be changed over". As my ROMs are 128K-ROMs, I guess the 64K-ROMs are the version without the FFT and other stuff.

So I'd suggest changing them and see what happens.

[Stonewerk]

I have repaired both models,  the PM3320 and PM3320A hardware are sufficiently different to merit having service manuals for both models. (This statement made for the benefit of those reading this thread, and not SaabFAN - who's already been through all this...)

Anyway, the original firmware (V2) in my unit is on 128k parts (27010), so the trace jumpers should already be correct. I've attached an image of the relevant area on the back on my A6 uP Board - it should match your board.

A question just occurred to me -  is there a board installed the A10 position (Option 2) of your PM3320A? There is none on mine.

[Stonewerk]

Oops! I just reread the thread, and see the answer in an earlier post - A10 is unpopulated in your unit, too.

Hmm, if there is a change in a PLS device, that's a bit problematic. I don't have anything in my lab that can read or program PLS105/82S105 PLDs (PALs and GALs - yes - but not the PLS') , but I may be able to get access to a compatible programmer from my former cohorts in engineering.

Can you get access to a suitable programmer over there - perhaps in you university EE department?

[SaabFAN]

Unfortunately, I am studying 3D Game Art, which is pretty far away from anything related to EE and my university has no engineering department (I'm studying at the SAE). So no luck there.
And I don't know who to ask at the big universities here (Universität Hamburg and Hochschule für Angewandte Wissenschaften). But maybe some other people here in the Forum know the right people to ask

[Stonewerk]

Okay. At this point, I'll consider the issue closed.

Without further input from those who have attempted the firmware change, the following conclusions are drawn from this experiment:

• Replacing the v2 firmware with the v4 firmware is practical -  the scope  powers up and passes its self test without error
• Some minor functions are added with the firmware change, e.g., the ability to change cursor markers from a "+" to "x".
• However, the firmware change alone fails to  enable the FFT math function.
• No detrimental impact to scope operation has been observed.

In my opinion, without a documented revision history, the benefits of upgrading the firmware are unclear. The differences appear subtle, with no performance improvements (nor degradation) noted. In other words, the change is likely unnecessary. On the other hand, I have not (yet) performed a comprehensive differential comparison.

Nevertheless, I would not expect the manufacturer to make firmware changes without significant purpose(s) - e.g., bug fixes, accuracy improvements,  additional functionality, etc.. But again, these are unknown.

I would encourage other owners of a PM3320A with older firmware to perform the firmware "upgrade" and to relate their findings here, noting any quantifiable differences. 

Meanwhile, I think we all owe SaabFAN a big ol' hunk of gratitude for taking time out from his studies to make the effort to post the  firmware images from his scope!

By the way, if anyone has - or knows where I can get - an extender card for this scope, please PM me. Thanks!

Danny Stone
Folsom, CA
USA

[SaabFAN]

I think the best way, and probably the cheapest, is to get some Europa-Format Vero-Boards with provisions for 96Pin-Connectors and build one yourself. Buying such cards is, at least in Germany, crazy expensive (over 100€ for such a card).
I found 96pin-Connectors for 5 to 9€ on ebay.

An alternative, which could also feature measurement-points, would be to design a PCB in Circuitmaker (or any other CAD-Software without limitations on size and Pin-Count) and let one of the cheap chinese manufacturers produce them. Shouldn't be too expensive and you have several boards to test several modules at the same time or sell those you don't need.

[tautech]

.
An alternative, which could also feature measurement-points, would be to design a PCB .....

I've done this on old CRO's with plugins and used ex PC IDE cables for the extender chopped up to suit.
You just need to identify the power terminals and ensure conducters are heavey enough to carry the current. 1 mm² should normally do the job.
The only other tricky bit is identifying and finding the correct socket.

[SaabFAN]

The traces on the boards are all pretty thin, so IDE-Cables should be able to handle the currents.

On another note: How much noise does your Unit show, Stonewerk? I get pretty consistent 1,2mV of noisefloor in all timebase-settings at 5mV/div. I don't know if that is good or just at the corner of going bad, but my Rigol DS1054Z has about 600µV of noise at the fastest timebase and increasingly higher noise at slower timebases.