Plasma Meter Trouble

[Loopzilla5]

Hi Everyone,

We suffered a power surge that took out multiple cards on the 4064G+. I'm repairing...

Plasma meters aren't working. I've got 263v at the 73/74/75 card system and at the meter cassettes. I've repaired all blown ±18v fuse resistors on the cassettes and they illuminate and switch correctly. I have great-looking ramps on the scope from the 73 card. Still no plasma action across the board. Any ideas? This is a tough one.

[horizonsound]

Possibly on the E74 switch and lamp logic card, which enables the anodes, and your selection of VU/PPM/VCA

Anthony.

[Loopzilla5]

I actually have a spare (NOS) 74 card and tried it today - no change. Will search more tomorrow. The 250v lamp on the 73(?) card comes on when the switch is on - that's all I see at the moment.

Got the DC-on-Minis solved, looking at Total Recall and meters through the week. Fixed the "pop" when changing status - that was a blown channel strip leaking DC into the Quad bus.


This power surge messed us up. How are your consoles protected?

[horizonsound]

Check that you have the +83V switching on the phase outputs of the E75 card. This will ensure the FETs and TR4, TR5 on that card have not blown.

Output is on pins 2, 7, 11, 16, 20, 26.

Do you have any sign of life on any of the plasmas?

I'm interested as I am currently building up a plasma system, which has lots of issues with it.

Anthony.

[Loopzilla5]

I replaced the TIP Pair and indeed have 83v. No plasmas yet...

There's good voltage and signal from the channels at each meter, but no plasma. It's something global - just have to find it.

[cleartrack]

Any luck?

I had the exact same thing happen (power related damage to one of the main plasma boards). I've tried replacements, myself and a few techs were unable to resolve it. Partially rebuilt all 3 of the E73, E74, E75 cards with all new components. The op-amp replacements may be a problem in my system (HA2-2645-5), though I've tried new ones.

[Loopzilla5]

Not yet - haven't taken much time to look at it in the last few weeks, but our problem sounds similar...