Fluke / Philips PM3394A Combiscope preventive maintenance

[srb1954]

It's a 16 bit CPU, the interesting thing is perhaps why they went with it given that they clearly needed more than 64k of firmware and (say) the 68000 was pretty mature by the time the range was designed and would have given them a flat 16MB of address space to play with.

Especially interesting that they didn't go with something like a 68000 as Philips second-sourced many of of the 68000 family chips. They also had their own 68000-based integrated processor, the SCC68070, which would have been well suited for this application.

I guess the instrument division of Philips just didn't talk to their semiconductor division.

[shakalnokturn]

If this can be of any inspiration:
https://www.eevblog.com/forum/testgear/old-philips-fluke-97/msg3260496/

I'd bet there are plenty of similarities between the old Scopemeters and Combiscopes on the remote control side of the subject.

Marrob released software to read/write calibration data and firmwares to the PM9x series.

[grumpydoc]

If this can be of any inspiration:
https://www.eevblog.com/forum/testgear/old-philips-fluke-97/msg3260496/

I'd bet there are plenty of similarities between the old Scopemeters and Combiscopes on the remote control side of the subject.

Marrob released software to read/write calibration data and firmwares to the PM9x series.

I must admit that I missed that post.

We know the undocumented commands are CF, DW, EM, EO, EX, PF, QC and QF - the command table starts just after 0x11E0 in the ROM

CF=Clear Flash; PF = Program Flash and QF=Query Flash would be pretty plausible and consistent with the scope meter. QC is possibly Query Cal though "PC" is definitely not Program Cal - it is "Program Communication" - i.e serial port parameters.

Anyone any suggestions for the rest?

The CPL list from the manual is
AS    Auto Setup
AT    Arm Trigger
CL    Calibrate
DS    Default Setup
GL    Go to Local
GR    Go to Remote
ID     IDentification
LL     Local Lockout
PC     Program Communication
PS     Program Setup
PT     Program text
PW    Program Wavefrom
QS    Query Setup
QM    Query measurement
QP     Query Print
QT     Query text
QW    Query Wavefrom
RI      Reset Instrument
RS     Recall Setup (internal)
SS     Save Setup (internal)
ST     STatus query
TA     Trigger Acquisition

The list in the ROM is:
AS, AT, CF, CL, DS, DW, EM, EO, EX, GL, GR, ID, LL, PC, PF,
PS, PT, PW, QC, QF, QM, QS, QT, QW, RI, RS, ST, SS, TA

Looks like a table of 8 byte entries - the AS text is at 11E2 - and my guess is that's the start of the table, but beyond that nothing is obvious.

[grumpydoc]

The table looks like this:


11e2  41 53 00 06 ca 12 00 00 ; AS
11ea  41 54 00 06 cb 12 02 00 ; AT
11f2  43 46 01 02 cc 12 04 00 ; CF
11fa  43 4c 00 06 cd 12 06 00 ; CL
1202  44 53 00 06 ce 12 08 00 ; DS               
120a  44 57 07 06 cf 12 0a 00 ; DW
1212  45 4d 00 04 d6 12 0c 00 ; EM
121a  45 4f 00 02 d7 12 0e 00 ; EO               
1222  45 58 09 03 d8 12 10 00 ; EX                 
122a  47 4c 00 06 e1 12 12 00 ; GL                 
1232  47 52 00 06 e2 12 14 00 ; GR
123a  49 44 00 06 e3 12 16 00 ; ID
1242  4c 4c 00 06 e4 12 18 00 ; LL
124a  50 43 06 07 e5 12 1a 00 ; PC
1252  50 46 04 02 eb 12 1c 00 ; PF
125a  50 53 00 0e ef 12 1e 00 ; PS
1262  50 54 02 07 f0 12 20 00 ; PT
126a  50 57 00 0e f2 12 22 00 ; PW
1272  51 43 00 02 f3 12 24 00 ; QC
127a  51 46 04 02 f4 12 26 00 ; QF
1282  51 4d 02 07 f8 12 28 00 ; QM
128a  51 53 01 07 fa 12 2a 00 ; QS
1292  51 54 02 07 fb 12 2c 00 ; QT
129a  51 57 02 07 fd 12 2e 00 ; QW
12a2  52 49 00 06 ff 12 30 00 ; RI                 
12aa  52 53 01 06 00 13 32 00 ; RS
12b2  53 54 00 06 01 13 34 00 ; ST - yes, before SS?                 
12ba  53 53 01 06 02 13 36 00 ; SS
12c2  54 41 00 06 03 13 38 00 ; TA



No idea what the other values mean (and, so far, haven't tracked down the code which accesses the table).

[Edzko]

In case anyone is interested: 

https://github.com/Edzko/CombiScope

Edzko

[Vince]

Looks nice, hopefully someone competent i.e. not me, will grab your source code and port it to Linux so I can use it 

In the mean time I guess my best option is a software GPIB "printer", think I sawx that somewhere, though that too might be windows only I can't remember...

[HighVoltage]

In case anyone is interested: 

https://github.com/Edzko/CombiScope

Edzko

Thanks

I downloaded the files, but how do I start it under windows?

[onre]

Reviving the thread, hope it's okay.

I have a 3384B with Math+ and extended memory, but no IEEE-488. The maintenance menu reports a 512 kB ROM. As far as I can tell, it works. Even passes AUTOCAL.

As this is my first DSO, I figured I might as well try to make the most of it. A quick look at the HP-GL library situation as of 2025 led me to roll my own, and I also wrote a small Unix/Linux program to communicate with the scope. Attached is a screenshot showing the current state of it. It's written in C, the only library dependency is XCB. Should be rather easy to get to run on anything that's even somewhat POSIX-like. It'll end up in a public source code repository sooner or later.

grumpydoc, I salute you for the disassembly and memory mapping effort! Do we already know how to dump the firmware image over RS-232, like civilized people do? Turns out Ghidra supports MCS-96 and I've used it for some disassembly projects in the past and thought I could take a look.

The only thing worth contributing I have right now is the user manual with added PDF outline, making it easier to find things quickly.

[HighVoltage]

I still have about 10 of the PM3394B in use.

Your software looks nice, would be good to use it over GPIB
I am still using the original FLUKE software over RS232