Neil Hampson Posted August 26, 2010 Share Posted August 26, 2010 Well, it's got around to fix-it time again and I have a broken Betapack 1 which I am hoping somebody can throw some suggestions as to a fix. As per the title, Channels 3,4,5&6 are permanently on full, a classic Triac fault I hear you cry... But no, the fault moves around when I swap the trigger wires so the fault exists before the triac cards, The wiring to the main board to the connector has also been disconnected to rule that out as well (the test dial on the front doesn't work either but I don't think that is related.) I have been around the circuit board and cleaned up any dry joints that were there, (One or two, nothing major)The first and most obvious common component is an LM324 which controls 3456, (checked out OK by substitution)I have also swapped out the other LM324 and the two other smaller white chips, but no change to the output. the pack seems to be in reasonable overall condition, there is some discolouration on the PCB around one of the bigger transistors and a couple of diodes, which would indicate a bit of heat damage, but the components have tested out OK and bear in mind the thing is 20 years old now. So, I hand it over to the general population for ideas what to check next. Photos to follow if required. A concurrent post has been automatically merged from this point on. One more thing I tested, all of the LM324s are getting the same + and - power.(as you can tell I'm convinced it's something to do with that IC.) Link to comment Share on other sites More sharing options...
pritch Posted August 26, 2010 Share Posted August 26, 2010 This any use? http://www.blue-room.org.uk/wiki/Betapack_Servicing Link to comment Share on other sites More sharing options...
Neil Hampson Posted August 26, 2010 Author Share Posted August 26, 2010 Thanks for that, I've just re-checked the big 100K's and they are well out, although not quite open yet. The layout of the Mk 1 is slightly different from the Mk2, but I'm guessing that the 4 2W resistors on the board are still doing the same job. Time for an RS order... I never found that thread when I did a search, possibly as I tried betapack 1, rather than just betapack. I'll re-post when I've changed the bits. Link to comment Share on other sites More sharing options...
jonhole Posted August 26, 2010 Share Posted August 26, 2010 Hi Neil, Drop Keith an email on keith.rogers@cooperindustries.com I'm sure he'll be able to help. He's off work tomorrow, but should reply on Tuesday. Cheers Link to comment Share on other sites More sharing options...
PaulDF Posted August 26, 2010 Share Posted August 26, 2010 I posted a pic with the resistors here a while back:http://www.blue-room.org.uk/wiki/Betapack_1If yours is different please can you add a pic?If you haven't already contacted Z88 it is worth giving them a shout as they will probably email you a schematic diagram for the betapack.Re the test dial, this just connects a source (15v?) to each of the 0-10v analogue inputs in turn from the din plug on the front. Did you try it with nothing plugged into the din plug? I have found my demux makes the test dial work unusually so have to unplug it first. Link to comment Share on other sites More sharing options...
ianknight Posted August 27, 2010 Share Posted August 27, 2010 I'd swap the 100k resistors anyway - if it's not been done since new and they are out of value, it's enough to throw the sync for those channels so the rack won't be acting reliably. Once you've done that, check the 15v regulator to make sure that it's giving out fifteen volts - important because one of the reference rails is derived from this rail. Whilst you're poking around that part of the Circuit board - check the two small electrolytic caps near the 15v reg for dry joints or for bulging (in which case swap them!). Lastly (before Keith takes over!) check the IC's at the right end of the PCB (near the molex's) for dry joints - these are the area's that I've seen most commonly cause problems with Beta 1's and after you've tried them (if it's still not playing) then it's circuit diagram, multimeter and prod time. If you dont have the means then I'm sure that Keith can recommend a service centre to send it to... Link to comment Share on other sites More sharing options...
Neil Hampson Posted August 27, 2010 Author Share Posted August 27, 2010 I have ordered the new 100Ks and should get them by Tuesday. The LM324's were luckily mounted on push in DIL holders so I was able to tezt those by substitustion as well. I've already been around the board for dry joints, the only other component that was suspect is the large(ish) transistor just to the right of the transformer has signs of burtning and was very loose on the board, it did test out fine so I put it back on (as I didn't have a spare to hand) I have also updated the Wiki entry to include link to the PCB photo referenced above Link to comment Share on other sites More sharing options...
Neil Hampson Posted August 31, 2010 Author Share Posted August 31, 2010 The resisitors arrived on Saturday afternoon, and I fitted them in last night (remind me not to try to solder on to PCB's after being at a festival for most of the day) The pack now works fine agian, it does have a slightly odd dimming curve, but I suspect that the preheat has been tampered with as the resistors have aged over the last few months/years.Thanks all, That saved a dimmer from the skip for £5. Link to comment Share on other sites More sharing options...
dtaylor Posted November 1, 2012 Share Posted November 1, 2012 Google found me the article on betapack servicing which seemed to describe the exact fault I was having with channels 3 and 4. being a reckless kind of guy with nothing to lose, I followed the instructions and replaced the 100k resistors and related capacitors. now ALL of the channels are permanently on! I am not experienced electronic engineer, but am competent with a soldering iron, so I am as sure as I can be that the work I have done is good. I am 99% sure I bought the right components to replace the 'faulty' ones. can anyone give me any suggestions as to what I might have done wrong? in hope. Derek. Link to comment Share on other sites More sharing options...
jonhole Posted November 1, 2012 Share Posted November 1, 2012 Hi Derek, Give Keith a call on 01633 833101 and he'll be able to tell you exactly what's wrong :-) Cheers, Link to comment Share on other sites More sharing options...
boatman Posted November 1, 2012 Share Posted November 1, 2012 This may be a silly question, but you didn't accidentally press all the test buttons in whilst you were repairing it? Link to comment Share on other sites More sharing options...
dtaylor Posted November 1, 2012 Share Posted November 1, 2012 Who is this Keith person and will he mind a random person from the internet ringing him out of the blue? The Test facility is a rotary switch rather than individual buttons, but thanks for the thought! Derek. Link to comment Share on other sites More sharing options...
handyandi Posted November 1, 2012 Share Posted November 1, 2012 You are a customer that owns one of their products & strange at it may seem in today's somewhat general shoddy customer service, Zero 88 are very good. Keith is their service manager (If I remember correctly) with a shed load of experience (again something in short supply these days), just give them a call! Link to comment Share on other sites More sharing options...
Nicktaylor Posted November 1, 2012 Share Posted November 1, 2012 I must say I bought a secondhand spares or repair unit thinking it would be the resistors etc. Sadly after a full refit of resistors I have exactly the same fault and left it in the back of the store! Keith Rogers has been with Zero 88 as long as I have been using/owning the kit! He is always very helpful when you have problems, to be fair as are all the other contacts there Link to comment Share on other sites More sharing options...
dtaylor Posted November 2, 2012 Share Posted November 2, 2012 Thanks to everyone who helped and to Keith for what will no doubt be a legendary short phone call. Within about 45 seconds after I had described what I had done, Keith had spotted the error of my ways and told me how to fix it. Cutting a long story short, I had over-zealously replaced too many resistors, mistaking a 1k up by the transformer for a 100k like the other 4. (In my defence it was the same shape and size...) Having replaced the original 1k from my discard pile I now have a 100% working dimmer again - fantastic! Keith - your legend lives on! Thanks. If I ever get asked to nominate someone for the queens new years honours, you're up! Regards, Derek. Link to comment Share on other sites More sharing options...
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