You can read the forward and reverse voltage drop across the diode array with an ohm meter on a diode-check scale. I'd advise testing it at the connections on the circuit board instead of trying to flex the fragile leads around any more than necessary.
Ok thanks Watthour! It'll be a while yet until I've got it all back together and turned back on, then I'll have to figure out exactly what you mean. I think you said in your first post on here to be very careful with this diode! So I read a few threads about it and like you've just said the fragile leads seem to be the concern, so I was trying to keep those steady when unscrewing it. I wasn't expecting it to break where it did! I don't know what the diode is made of but it just looks like a plastic bit which broke off that I'm hoping was only there to enable the screw to secure the diode to the heatsink.
When I was adding new heatsink compound to the TO-3 transistor pads, some of it seeped through to the other side of the heatsink when I secured them (even though I tried not to use too much). Does it matter if the paste gets onto the pins of the transistor or will it affect the contact?
Yeah I definitely put too much on. If its got inside where the pin is pushed in, I thought that would be bad. I've read on here so many times how important it is to clean all the contacts.
I might take them off and do them again, but that paste gets everywhere, and I have to take the heatsink out again and bend all the wires again and risk one of them breaking off.
I might take them off and do them again, but that paste gets everywhere, and I have to take the heatsink out again and bend all the wires again and risk one of them breaking off.
I'm starting to look at the equalizer board to replace the transistors Watthour mentioned, I want to replace the electrolytic caps too. So far I've been using Panasonic FC caps, but this board has two of the CEANL low leakage ones. On the recap lists here, I see most people use the Nichicon UKL ones here, but element14 doesn't have UK stock of these. Are there any good alternatives I can look for?
39cross
Well-Known Member
I recall reading a post from mark THE fixer, he ran a test with KL's versus non-low leakage, the KL's were quieter. If you can get the KL's to replace the CEANL's why not? Have you tried http://eu.mouser.com/?
Hiya. Yeah I read that. Also read some people think the Elna Silmics are better. The choice of caps seems like a controversial subject. I've read most threads on here about it.
I can order from Mouser - there is a UK site, but I think it's still shipped from USA. There is a £12 delivery charge and it takes a few days. I've been so impressed with Farnell so far. Delivery is free and next day. I placed an order for two transistors, for about £1 and it was shipped within 10 minutes and arrived the next morning. It must have cost more just for the jiffy bag they came in!
I can order from Mouser - there is a UK site, but I think it's still shipped from USA. There is a £12 delivery charge and it takes a few days. I've been so impressed with Farnell so far. Delivery is free and next day. I placed an order for two transistors, for about £1 and it was shipped within 10 minutes and arrived the next morning. It must have cost more just for the jiffy bag they came in!
I suggested Farnell since they have an actual, real warehouse in the UK. They are "Newark" in the US. Mouser seems to have a lot more choices, but if you can fill your needs with Farnell it just makes sense. Save the Mouser orders for when you really need something the others don't have, then stock up to make the shipping cost more palatable. Load up on lamps, fuses, caps, and whatever else to make it practical. I still use Newark for industrial electronics that Mouser doesn't handle.
Yes that's what I've done. I saw that if you spend over £33 the delivery is free, saving £12. So I added the big filter caps to my order. I don't know if I really need them, but noticed people tend to change them when doing a recap.
I'm still missing the C18 cap from the power supply board, so while I wait for it to turn up I thought I'd clean things up a bit. I reapplied the termal paste to the output transistors where I had used too much. It was a messy job, it gets everywhere!
Then I followed the deoxit guide. Gave all the switches and front panel a clean too. It's looking very nice now!
Does anyone have any recommendations for cleaning the metal chassis? I noticed there are some black marks, especially around the transformer. Not sure whats it is, but it may get worse if I leave it. Any good cleaning products I can use? Thanks!
I'm still missing the C18 cap from the power supply board, so while I wait for it to turn up I thought I'd clean things up a bit. I reapplied the termal paste to the output transistors where I had used too much. It was a messy job, it gets everywhere!
Then I followed the deoxit guide. Gave all the switches and front panel a clean too. It's looking very nice now!
Does anyone have any recommendations for cleaning the metal chassis? I noticed there are some black marks, especially around the transformer. Not sure whats it is, but it may get worse if I leave it. Any good cleaning products I can use? Thanks!
That appears to be pitting/corrosion through the zinc plating. There is not much to be done about it other than to stop it. The yellow chromate zinc can be emulated by mixing and thinning paint and dabbing the pit marks after cleaning, and that will help stop further corrosion, but may only slightly blend the blemishes. If you are really particular, the unit could be completely disassembled, blasted, etched, and plated again in zinc chromate. That would require you to find a plater who deals with stampings so as not to make a bigger mess of it than you would want to deal with.
Thanks Watthour. Zinc chromate! I can't believe how much you know about this receiver! It thought it was some sort of corrosion. I think completely disassembling it is too difficult - how would I get all those wire wraps off (and back on!)? And I'd have to make sure each one went back in the right place! I'm not to concerned about how it looks (within reason) - it's on the inside and only in a small area, I'd just like to try to stop it getting worse.
So when you talk about dabbing the marks with thinned paint - what sort of paint would you recommend? I've read a bit about zinc chromate. I could buy a primer which should apply well, but I don't think would look too nice.
So when you talk about dabbing the marks with thinned paint - what sort of paint would you recommend? I've read a bit about zinc chromate. I could buy a primer which should apply well, but I don't think would look too nice.