Good Morning all,
I'm looking for insulator pads for my amplifier. Long story short was checking for an issue with it and ended up creating one lol. I took off these plastic looking sheets off the bottom set of transistors, and now the amp consistently blows its 10 amp fuse. Can I find this part or at least a good alternative in a hardware or building supplies store? This is for a denon receiver btw. Thanks.
I'm looking for insulator pads for my amplifier. Long story short was checking for an issue with it and ended up creating one lol. I took off these plastic looking sheets off the bottom set of transistors, and now the amp consistently blows its 10 amp fuse. Can I find this part or at least a good alternative in a hardware or building supplies store? This is for a denon receiver btw. Thanks.
Do you mean insulating pads for the output transistor?
If so then they are available for most common transistor packages such as TO3, TO220, TO264 and so on.
https://cpc.farnell.com/c/electroni...hermal-lnterface-materials/thermal-insulators
If so then they are available for most common transistor packages such as TO3, TO220, TO264 and so on.
https://cpc.farnell.com/c/electroni...hermal-lnterface-materials/thermal-insulators
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Morning, and yes I mean those. I believe the ones I took out are mica based though. I really don't want to go through the hassle of ordering since I'll have to import these into my country. I'm wondering if there's an alternative to this. Can I find some sort of plastic or silicone sheet readily available at a store and cut it to fit the transistors?
I can't just think of anything common that would be suitable. These are specialist items designed to have excellent heat transfer characteristics while also allowing the device to be tightened down correctly without risk of the material compressing and the device become 'loose'. They are also designed to operate at very high temperature if needed.
They look a simple part but are absolutely mission critical in the scheme of things.
They look a simple part but are absolutely mission critical in the scheme of things.
What happened to the old ones?
If you can't re-use, maybe its time to donate to this great forum ;-)
Keratherm Transistor Insulators – diyAudio Store
BTW if you re-use the old ones, before switching on, measure resistance between the transistor metal tab and the chassis. It should be many megohms or infinite (often shown as 'overload' on the DMM).
Jan
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Most Farnell parts are available from Newark with the same part numbers in many cases. They are both part of the same company.
I would be tempted to open the transistor selector and see if there is an equivalent in an ISO package.
Just type in the spec from the data sheet.
The isolated ones do not command such a high price and best of all they have factory fitted insulating washers. Just a little spot of CPU paste will do the job.
I would be tempted to open the transistor selector and see if there is an equivalent in an ISO package.
Just type in the spec from the data sheet.
The isolated ones do not command such a high price and best of all they have factory fitted insulating washers. Just a little spot of CPU paste will do the job.
The fully insulated ones (often with -F from full pack in the type number) are also much lower in allowed dissipation and, more important, have much smaller SOA. Don't.
Jan
I threw them away when cleaning the amplifier. I didn't know their purpose thought it was just used as a medium for carrying the thermal paste. 🙁
From the service manual, the receiver uses SK 2SD2560 and SK 2SB1647 transistors. The datasheet says they're 19.9 mm ± 0.3mm x 15.6 mm ± 0.4 mm.
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Those are Sanken manufactured transistors and have a standard TO3P outline.
https://uk.farnell.com/bergquist/k6...0?MER=bn_level5_5NP_EngagementRecSingleItem_1
https://uk.farnell.com/bergquist/k10-104/thermal-pad-to-3p/dp/936753
https://uk.farnell.com/bergquist/k6...0?MER=bn_level5_5NP_EngagementRecSingleItem_1
https://uk.farnell.com/bergquist/k10-104/thermal-pad-to-3p/dp/936753
FIRST question you should answer is: WHICH IS:
I am quite certain you can buy mica and thermal grease locally, but you´ll have to answer your location first 🙂
Suggestions are very Country specific.
I am quite certain you can buy mica and thermal grease locally, but you´ll have to answer your location first 🙂
I live in The Bahamas. It's not far off from the USA. We have hardware stores and tech stores here and there.
The Bahamas is not a backward land. 400K people with income not far from US and Canada. Must be mica insulators on the island, if only for many boat-radios and a few TV sets.
It IS odd that neither DigiKey or Mouser lists Bahamas as a destination. Nor does Element 14, but you could contact their Export desk.
https://export.farnell.com/help-faqs
It IS odd that neither DigiKey or Mouser lists Bahamas as a destination. Nor does Element 14, but you could contact their Export desk.
https://export.farnell.com/help-faqs
I usually use a courier, I just don't like the customs rates on top of it. It's 45 percent for parts and then a 12 percent vat charge. The pads are cheap though so it shouldn't be expensive to import.
If these really were percentages, that's fair and I wouldn't worry about it.
In Switzerland, we have a (not enforced) rule that lets the customs charge a flat $40 "processing fee". That hurts. Luckily, they're just too lazy to bother... 🙂
In Switzerland, we have a (not enforced) rule that lets the customs charge a flat $40 "processing fee". That hurts. Luckily, they're just too lazy to bother... 🙂
What a strange economy. "Electronics" of course means "appliances". Sifting through the blenders and hoovers, the few hardcore radio-guys seem to be "closed permanently". Boat radio seems to be dominated by US shops, some of whom "will travel", but I'm sure to install a $3K marine GPS, not $3 of mica. And yet, they might agree to call when they are on your island and hand you an envelope.
OK, I guess The Bahamas is 1/3rd the population of Maine and has less money per capita, so 1/6th the total market. There's a lot of services and parts I can't get near here. I'd have to drive a long way to find a hard-core radio shop, maybe out of state. Which from the Bahamas, would be Florida.
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