capristeve Posted June 28, 2016 Report Share Posted June 28, 2016 hi all, hoping you can help have two aging beta 1s, they get fairly light use in the school where I work, 2 consecutive channels are constantly on, I bought some triacs and fitted to the relevant channels but did not solve the problem the triacs I removed are T2513MK, and the ones I fitted in their place are BTA25600B so my questions are have I fitted the right triacs? and could I have wired them incorrectly? could there be another fault? any help with this will be greatly appreciated steve Quote Link to comment Share on other sites More sharing options...
kgallen Posted June 28, 2016 Report Share Posted June 28, 2016 Did both channels fail at the same time before you replaced the triacs? If so, maybe a sync circuit problem rather than triacs? I'd take a look at the infamous 100k sync circuit resistors. http://www.blue-room.org.uk/wiki/Betapack_Servicing http://zero88.com/forum/topic/3709-betapack-1/#entry27190 Kevin Quote Link to comment Share on other sites More sharing options...
capristeve Posted June 28, 2016 Author Report Share Posted June 28, 2016 yes! both channels went together (3&4) how involved is this job? swapping the triacs was easy, im assuming some solder may be involved? Quote Link to comment Share on other sites More sharing options...
kgallen Posted June 28, 2016 Report Share Posted June 28, 2016 If you can solder, swapping the resistors is pretty straightforward. You have to remove all of the screws holding the PCB into the chassis to get to the solder side. I've done 4 Betapacks (1's and 2's) and I don't recall them being hard - the Betapack 1s I think were a bit easier as there is more room. Just make sure you get the correct VR rated components as per my link. Don't just buy any old 100k 1W resistors as they are across mains voltage. If you've got an ohmmeter, you can get an idea if there is a problem with the resistors - there are 4 in there so you can compare readings - but don't expect to measure 100k when they are in-circuit. Replace all of the 100k resistors not just the ones you think have failed. It'll cost you a couple of pounds to buy the correct resistors. Kevin ps Where are you in the UK? Quote Link to comment Share on other sites More sharing options...
capristeve Posted June 28, 2016 Author Report Share Posted June 28, 2016 thanks for the info, im based in Dorset, i'll have a chat with our tech department and see if its something they can handle Quote Link to comment Share on other sites More sharing options...
kgallen Posted June 28, 2016 Report Share Posted June 28, 2016 Ok, can't offer to fix it for you as you're not local to me. If your Tech department can't fix this then get a better Tech department because if the resistors are the fault then it's a straightforward fix! Kevin Quote Link to comment Share on other sites More sharing options...
capristeve Posted June 30, 2016 Author Report Share Posted June 30, 2016 ive opened up the pack and one of the resistors in reading different to the other three! reckon I can handle this, thanks for the advice, given that this is the first problem ive ever had with this kit, its testament to zero 88 build quality! Quote Link to comment Share on other sites More sharing options...
iank99 Posted July 1, 2016 Report Share Posted July 1, 2016 Don't swap just one resistor! Really.... Don't... Do all four resistors because otherwise you'll be opening the pack again and removing the PCB to swap another one within 6 months - guaranteed! Quote Ian Knight aka The Service Guy - www.serviceguy.co.uk Link to comment Share on other sites More sharing options...
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