EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: reddish75 on September 22, 2022, 03:19:23 pm
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I am finally thinking about refurbishing an Audio Research D76 someone gifted me and am wondering on the best way to replace the power supply caps (x6 600uf 300v) they are five pin I think old Mallory caps. I have seen an adaptor someone made for a broken Tek scope but I'm not sure they would be suitable for the voltage I need as they replaced 75v caps (please see pic) the other option seems new caps of that value and voltage tend to be snap on would be to drill the pcb and jumper one terminal across. Any thoughts?
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http://www.rsdsound.co.uk/product/axial-to-radial-electrolytic-capacitor-adapters/ (http://www.rsdsound.co.uk/product/axial-to-radial-electrolytic-capacitor-adapters/)
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A lot of guys just install new modern capacitors under the chassis and leave the originals in place but electrically disconnected. If you want to get fancy you can disassemble them, pull out the guts and stuff modern parts inside them, usually new capacitors are smaller and can fit in the old can.
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Imho you could just put a new capacitor into positive and one of the negative holes which match the pin pitch the most. Of course it does not work if you want to retain original look.
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Irrc, on some Tek 400 series scopes, the PCB uses capacitor negative tabs for trace continuity. Not a problem, but you do need to check and, if necessary, jumper the pads to maintain continuity.
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I've made adapter PC boards then foolishly realized the new snap-in cap has 7.5mm or 10mm lead-spacing and can just fit right on the main board between two (old) pins. Try measure it. I add jumpers if required to join the extra case pins.
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A lot of guys just install new modern capacitors under the chassis and leave the originals in place but electrically disconnected. If you want to get fancy you can disassemble them, pull out the guts and stuff modern parts inside them, usually new capacitors are smaller and can fit in the old can.
This was thought about and I do like the idea in keeping the original look but I don't think I'll go down this route as I like to know everything is installed properly and will last.
Irrc, on some Tek 400 series scopes, the PCB uses capacitor negative tabs for trace continuity. Not a problem, but you do need to check and, if necessary, jumper the pads to maintain continuity.
Good information to keep in mind but it's not a Tek scope it's a valve amplifier
I've made adapter PC boards then foolishly realized the new snap-in cap has 7.5mm or 10mm lead-spacing and can just fit right on the main board between two (old) pins. Try measure it. I add jumpers if required to join the extra case pins.
Problem is the caps have individual cut outs on the chassis which they go through although one pin will line up the other wont
http://www.rsdsound.co.uk/product/axial-to-radial-electrolytic-capacitor-adapters/ (http://www.rsdsound.co.uk/product/axial-to-radial-electrolytic-capacitor-adapters/)
Thats a good adaptor but not the type I was looking for
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Has anyone used the adaptor in post one for 300vdc + or have an opinion about its suitability?
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Problem is the caps have individual cut outs on the chassis which they go through although one pin will line up the other wont
Then I would lead form negative lead very close the the can, maybe put some insulation on the lead. Then before soldering put a blob of electronics grade or just usual neutral silicone under the cap for mechanical support.
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Good information to keep in mind but it's not a Tek scope it's a valve amplifier
That doesn't mean it's the only place it has ever been done, always check. The consequences of an open 0V trace on a valve amp PCB could be considerable.
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Good information to keep in mind but it's not a Tek scope it's a valve amplifier
That doesn't mean it's the only place it has ever been done, always check. The consequences of an open 0V trace on a valve amp PCB could be considerable.
Absolutely! Just wasn't sure you realised it wasn't a scope