DL#094 - 1980s Quantel Paintbox V-Series Teardown & Repair Part 1

In this video i start looking at the Quantel Paintbox V-Series Harriet system. The Paintbox was a video based graphic editing system used throughout the world for TV production.

This unit needs repair and i also discuss at progress on that too!

Painting With Light:

[frankowalker]

I saw Kenny Everrette do a small documentary about Quantel in the late 80s/ early 90s.
I've wanted one ever since.

[Corvid]

Gorgeous circuit boards! Reminds me of the inside of my Ensoniq ASR-10, a sampler from the early 90's.

[philpem]

Here's an idea from my years of improvising... If I didn't have my logic analyser or it was hobbled (as it currently is, I need at least one new HP 16717A acquisition card), I'd get a bunch of 74HC573 latches from stock and wire them to the CPU address bus. Latch the address bus when the /BERR (bus error) line goes low -- this should leave you with the address of the bad access on the output of the latches. Add a few LEDs and you can read it off in binary (or if you have some TIL311s kicking around... wire those up and read it off in hex). For extra fluff, you could wire up a S/R latch which is cleared by /RST and set by /BERR and drives an LED ("bus error seen"), but the "Bus Error" output from the mon-ROM would be as good.

With the 16717A + 16700A? Use that Eurocard debug connector to get at the bus, trigger from negative edge of /BERR, 90% prestore. That way, you'd see everything leading up to the bus error, followed by a few accesses after when the CPU went for the BERR vector and trap handler.

You're probably right about the Eurocard connector next to the CPU. More recently, that's been done with Mictor connectors, but the general idea remains the same. It's an easy way to get access to the CPU bus to debug the firmware/monitor ROMs (and even the OS kernel, to an extent) using a logic analyser during initial board bringup. You can even wire the board up to an ATE (automated test equipment) jig and test the thing on a production line with a setup like that.

You could even pull the CPU chip, wire some DIP switches (don't forget the pullups/pulldowns!) to the address and control lines on the "debug" connector and see if the data/address signals on the VME bus connector are reasonable. If I was doing this, I'd be trying READ transactions only, ideally with the CPU board outside the chassis (testing in isolation / fault localisation).
Also, swap out those NVRAMs! Last time I checked, they were still current parts (i.e. available off the shelf from Farnell). Some systems will do absolutely crazy things if the NVRAM batteries are flat -- old Sun workstations are the first example that springs to mind.

Geez, that was more than I started out wanting to write... I'm an embedded systems engineer... can you tell? :P

[chrisnorth]

FWIW, the V-Series I have has a separate unit, "Ramcorder" which connects to the main unit to store 300 frames or so of video. It's a quite a big unit, same size as the main.

[jensmarkwart]

It would be really nice if you could also show a bit of the debugging process, talking about memory map, show serial output etc. :) Nice video series so far ;)

[DanielRowe]

This looks like a really interesting problem.

[DAVIDGREGORYKERR]

Is the processor using the PowerPC processor or was it based on a SUN Microsystems Processor or what, did SKY PLC own this one, I think that the RGB output board is just 3xR2R networks for RED, GREEN and BLUE, The processing that the QUANTEL does can now be done in SONY VEGAS video editing package. would it be possible to get a PowerPC version of GhostBSD 10 and use that as it is based on BSD UNIX which is what DEC VAX UNIX is based on, your memory error might be an out of memory error, Why don't you contact SKY PLC and see if they can help you.

[jaywalt]

I commend you on your craziness!. I mean that in a complimentary way as this is a very good video series so far. Does NDA mean nondisclosure agreement? Does quantel still exists? Have you any effort to contact them or these people who are holding the schematics and manuals you need? You would think they would be willing to help you get this running just because its a great peice of history. Its ridiculous as I dont tbink any of the technology is relevant in todays age and what could you possibly do with the info. Maybe you need to sign an NDA to get access. Lol! I hope you get it figured out!

[station]

Could be as simple as a duff 74xx244 on an address bus, or 74xx254 on a data line.

[iamdarkyoshi]

Should have said you needed a logic analyzer, I have a box full of them. Unopened.