Swapping a Triac

[luebug]

How do I swap a Triac on a Zero 88 Betapack 1?

 

Does anyone have photos?

 

I've not opened it up yet but I have the old 'channels stuck on' problem and from reading threads in the blue room it seems this would be a good place to start.

 

Any advice would be gratefully received.

 

Many thanks,

 

James

[patrick_keys]

Which channels are stuck? If you've got pairs of channels stuck (e.g. 3+4, 5+6) it's more likely to be one of the resistors connecting the sync circuit to the mains input - R3 for channels 3+4, R6 for channels 5+6. They should be 2k2 high-power resistors - 2 or 3W from memory, but you should check this.

 

You need to pretty much disassemble the rack to get to the main PCB. Remember to disconnect the power first, and observe the usual safety precautions. This of course comes with the standard warning that if you're not sure what you're doing or your ability to do it safely, then ask someone else to help or contact Zero88 for support.

[numberwrong]

Are you absolutely sure the pre heat isn't set to 100% or there is no other setting or memory making the channel stay on?

 

You don't want to go though all that effort only to find the problem was solved with a few button pushes!

[ianknight]

Which channels are stuck? If you've got pairs of channels stuck (e.g. 3+4, 5+6) it's more likely to be one of the resistors connecting the sync circuit to the mains input - R3 for channels 3+4, R6 for channels 5+6. They should be 2k2 high-power resistors - 2 or 3W from memory, but you should check this.

 

You need to pretty much disassemble the rack to get to the main PCB. Remember to disconnect the power first, and observe the usual safety precautions. This of course comes with the standard warning that if you're not sure what you're doing or your ability to do it safely, then ask someone else to help or contact Zero88 for support.

 

Almost there... the wiki here tells you where to look.

 

Essentially - single channel stuck on = triac but pairs of channels = resistors.

[Nicktaylor]

I thought they were 100K resistors, assuming this is the problem and it is very common, replace all at once. I think it is maybe four per pack. Otherwise you will mend one pair and the ageing will take out another shortly after. Five years of use is about the norm. I have tried fitting over rated resistors (power) and so far that has worked. Channel one and two go direct so the problem of resitors never effects that pair so if something goes wrong there it is not resistors. The triacs are very simple to replace. Make sure you have some heat compound between the triac and the heatsink and push on three spade connectors. Getting into the case is aproblem first time but once you know what part you are aiming for you will know which screws to undo!

[PaulDF]

Yep, they are 100K resistors used in the timing circuits.

http://www.blue-room.org.uk/wiki/Betapack_1

 

Back to the OP, do you have 2 channels stuck on full or just 1?