Found some old Tektronix TDS7XX processor boards Possible to bench test ?

[radioguy123]

Found some old Tektronix TDS 5XX 6XX 7XX processor boards. Not sure which model.
The numbers are: 679-4349-00, 679-4003=00 and 679-3488-00
I also have a couple of power supplies from these old scopes.
Is it possible to test these alone on the bench ?
Hooked them up with their ribbon cables and vga cable and they do boot up.
I get a few splash screens then the 7 segment displays halt and nothing.
Is there a dip switch setting that will just let them boot far enough to show firmware version or something.
Thanks

[radioguy123]

Found some interesting info on the TDS dip switch and 7 segment display.
All along in an old TDS520 manual I had.
Still can't find a combination that will keep something up on the screen for display testing.
The processor boards just run through the first part of the initialization and goes blank.
I know someone on this forum was using a bare bones unit with just the processor board for testing
and I can't remember who that was.


The Columbia primitive input is an eight bit dip switch (S1001) on the A11
DRAM Processor/Display board. When the system powers up the system
processor honors any special requests made by the dip switch. The eight switches
are active in the open position.
Table 1–27: DIP Switch Options
DIP Selection (8–1) Action
0010 0000 Enter SDM Monitor via the GPIB
0011 0000 Enter SDM Monitor via Console RS-232
0110 0000 Expand error log and increase diag messages
0101 0000 Do not attach the ethernet
0100 1000 Do not add extra ram to pool
0100 0100 Do not execute diagnostics
0100 0010 Do not execute higher level code
0100 0001 Do not execute system ram test
1X00 0000 Loop or Skip ALL bootrom Tests
1X00 0001 Bus Control Read
1X00 0010 Kernel Ram Test 1
1X00 0011 Kernel Ram Test 2
1X00 0100 Kernel Ram Test 3
1X00 0101 Bootrom Check Sum
1X00 0110 Bus Error Timeout Test
1X00 0111 Write Bus Control (open)
1X00 1000 Interrupt Mask Register 1
1X00 1001 Miscellaneous Register
1X00 1010 Timer Interrupt (Auto-Vector)
1X00 1011 NV Ram DSACKS
1X00 1100 Flashrom prog. voltage applied. NV Ram is write protected.
1X00 1101 Flashrom DSACKS
1X00 1110 Flashrom Check Sum
1X10 0000 Loop or Skip ALL Kernel Ram Tests
1X10 0001 Loop or Skip ALL Kernel Tests
1X10 0010 *Walk 7 Segment LED
1X10 0011 *Display Processor Version Number
If X = 1 (open) – skip (do not execute) test(s).
If X = 0 (closed) – loop on test(s).
* executes forever – power must be cycled to stop test



The Columbia primitive output consists of a 7 segment LED (DS1) on the A11
DRAM Processor/Display board.
Table 1–28: A11 DRAM Processor/Display LED (DS1)
LED Display Explanation
Decimal Point (DP) When this precedes one of the hex numbers, the particular test the number represents has
failed.
.E This indicates an exception
 .11 This indicates an interrupt
.P This indicates a non maskable interrupt
 .8 Displayed at power-up or reset
0 First displayed after power up
1 Bus Control Read diagnostic
2 Kernel RAM 1 diagnostic
3 Kernel RAM 2 diagnostic
4 Kernel RAM 3 diagnostic
5 BootROM Check Sum diagnostic
6 Bus Error Timeout diagnostic
7 Write Bus Control diagnostic
8 CPU Interrupt Mask Register diagnostic
9 CPU Miscellaneous Register diagnostic
a Timer Interrupt diagnostic
b NV RAM Dsacks diagnostic
c FlashROM programming voltage is applied. The NV RAM is write protected.
d FlashROM Dsacks
e FlashROM Checksum

Table 1–26: Troubleshooting Procedure For LED Display
Test Name
LED Display
(a failed test is
preceded by a
flashing decimal)
A11 DRAM Processor/Display
Troubleshooting Procedure
Bus Control Read 1 Bus Control Register
Kernel RAM 1 2 Kernel RAM
Kernel RAM 2 3 Kernel RAM
Kernel RAM 3 4 Kernel RAM
BootROM Check Sum 5 BootROM Control
Bus Error Timeout 6 CPU Bus Error
Write Bus Control 7 Bus Control Register
CPU Interrupt Mask Register 8 CPU Interrupt
CPU Miscellaneous Register 9 CPU Interrupt
Timer Interrupt a Timer Interrupt
NV Ram Dsacks b Bdsack
FlashROM programming voltage is applied. NVRam is write protected.
c On the A11 DRAM Processor/Display board
press S1002 towards the back of the
oscilloscope and cycle power.
FlashROM DSACKS d Bdsack
FlashROM Check Sum e FlashROM
ID Register
The LED displays the A11 DRAM Processor/Display ID in hex: the
most significant nibble (4 bits) first and then the least significant
nibble.

[fenugrec]

If you haven't, you could try connecting to the "service console port", you should see the vxworks boot messages, and possibly even get an interactive "shell" of sorts.

[radioguy123]

Hi fenugre
All I know at this point is that after the initial boot up splash on the screen the 7 segment stops moving and it seems in a halted state.
The screen it completely dark but the monitor I'm using didn't say lost signal. So there is signal there it's just black.
Don't you have to build some kind of uart board to use the serial console. I'll look into that.
If I remember there was a member called Cap here that was using a partial scope consisting of just a processor board and power supply for display
trouble shooting. When his unit booted up there was the scope main display minus a trace. That's exactly what I need to do plus test these boards.
thanks

[fenugrec]

Don't you have to build some kind of uart board to use the serial console.

Depends; if you have an "Option 13" board with RS232, I think all I had to do was rewire a pcb-edge connector and connect it to the service port.
I used the pinout from this post :
https://forum.tek.com/viewtopic.php?f=568&t=137307&start=20#p279787

Unfortunately I can't help with the specifics of running the A10 cpu board with nothing else... I would've assumed you would need at least the Acq board too, because fairly early in the boot process it needs to talk to it.

[Johnny10]

Why not buy a parts unit that has the acquisition board, graphics unit and other boards you need a build a complete oscilloscope.
Your missing the acquisition board.
That's why you can't get any further on the LED.

You might even pick one of the boards to sell to pay for the parts you need.

I started with a couple of 784D units with mixed parts a few years back. Took parts from two different units and made one great scope and sold it.

Read through the threads and match acquisition boards of I believe one of the OP said they could match any processor board with any CPU board. Can't remember now.

Search 754, 784D acquisition boards and you will find the results.
Tons of info available for these scopes.

[radioguy123]

fenugrec
All the boards have that console edge connector. So you are saying the uart is already on the board. All I need is to make a cable ? If this is just a serial port then there should be TX, RX and ground, possibly handshake lines. I need to research this more. Do you think when the board is in the blank screen mode that the console would be active ? I don't think you could use the console while initial boot I don't know. When the 7 segment display stops moving is the processor waiting for more input ? Or has it just crashed ?

Jonnny10
I do have one acquisition board. The number is 671-3461-03. I'm not really sure what this board is for. Maybe TDS744 ? You have some really good ideas here. Probably some of these processor boards could be used with multiple acquisition boards. Boy if I knew that and how to flash new firmware I would really be in like flint. But sorry to say I'm just not at the stage where I would be comfortable doing those things. What I really need to do is be able to determine what these processor boards can work with and what the firmware revisions are. Until I can do that I can't do anything.
Do you think I could attact this acquisition board to any of these and I would get past this road block ? I will give that a try.

thanks everyone for some good ideas.

[Johnny10]

There is a list of Tek numbers and boards that match. I'll see if I can find it.

Search says your acquisition board 671-3461-00 is for TDS744A Only

679-3488-00 is for TDS744A, 784A

Now you just need to find connectors and ( did you say you have power Supplies? )

There is a parts unit on eBay for Make offer 191 right now.
You can ask what is missing and see if something like this fits your needs.

[radioguy123]

Thanks Johnny10 for the reply.
I'm not seeing the ebay listing you describe. Probably sold already.
I will rig up a test setup so I can attach the acquisition board and see if I get a display with some errors.
I'm not sure if it is just a firmware thing but some of the newer scopes the processor boards
have to be used with a particular acquisition board or no go.
I'll try this tomorrow and report back
thanks

[Johnny10]

The Service Manual

https://www.tek.com/oscilloscope/tds684a-manual/tds684a-tds744a-tds784a-service-manual

If you look at the end of manual where it says replaceable parts. You will see your boards listed.
I took the info I gave you from here.

[Johnny10]

https://www.ebay.com/itm/154450724382?hash=item23f5fb061e:g:qXQAAOSw~ilgnD3D

Its just an idea not trying to tell you what to do.

[Johnny10]

From Service Manual

[fenugrec]

All the boards have that console edge connector. So you are saying the uart is already on the board. All I need is to make a cable ?

No, what I mean is, the Option 13 board has the necessary circuit (a MC68something DUART and other stuff) to give you an rs232 console, but you need to rewire its connector and hook it up to the service port edge-connector. Look at that thread I linked, it explains it in detail.

[radioguy123]

Hey fenugrec I did look at the link. Yes I thought a uart board would be required. I don't have any of those. Saw a board with the 68681 uart that someone was selling but the links are all dead. I'll look for an option 13 board but as of yet haven't found one.
And you guys are all correct. The A10 cpu board does need to talk to the acq board to fully boot up.
I have one acq board and all 4 of the cpu boards do boot up now with a diagnostic log saying cpu fail acq fail and front panel fail. Don't have a panel connected. Would be nice to had a front panel then I could have continued past the diagnostic screen.
No other information was gotten beyond this point except that the clocks all seem to be running.
I'll continue this testing once I've found a dead unit with at least a front panel assy. that works.
Cap if you monitor this forum I would like to get some info on how you were able to run with just the cpu board.
Thanks all

[Tantratron]

There is a list of Tek numbers and boards that match. I'll see if I can find it.

Search says your acquisition board 671-3461-00 is for TDS744A Only

679-3488-00 is for TDS744A, 784A

No idea what happened to the project radioguy123 but the two other processor boards he mentioned in his first post(679-4349-00 and 679-4003-00) are for C or D only TDSxxx serie using 68040 processor.

This is based from my own experimenting, repair of 9 different models (TDS510A, TDS784C, TDS794D, TDS520D, TDS540C, TDS754D and TDS714L).

Albert