LFazio51
Active Member
The center pin, which is the trace that definitely looks separated is, and the leg to the the right has continuity. If heat has caused this I would think it's probably best to just replace these transistors, don't ya think.
CR1020 Restoration Guidance
The center pin, which is the trace that definitely looks separated is, and the leg to the the right has continuity. If heat has caused this I would think it's probably best to just replace these transistors, don't ya think.
Thats one of the 2020 SB's - replacing the two pass transistors.
Going to have to take a little extra care when desoldering. Solder sucker could be to aggressive.
LFazio51
Active Member
The one with the bad trace is TR715 (D880 is the marking on it) and the other one is TR712 (D284 is the marking). TR713 and 714 are situated directly in line towards the rear of the unit. Should 713/714 be replaced as well? If you have a source for the TR712/715, please share if you don't mind.
LFazio51
Active Member
I'll use some Techspray wick when removing them - thanks for the "heads-up" on the removal technique.
Possibly D234.. that would be the OEM original part # .
These are more than adequate for the task. TR712 and 715 are the same.Part number.
https://www.mouser.com/ProductDetai...GAEpiMZZMshyDBzk1/Wi4G1GLBZKHK1aaGJ%2bHYgaG4=
LFazio51
Active Member
Awesome! As I'm coming to understand from you! I'll buy these and be very delicate when replacing.
Yes. And plan for the worst.Hope for the best....
stay tuned...
LFazio51
Active Member
Say Avionic, I've been preparing my list of items to be purchased from Mouser and I can't seem to locate filter capacitors with the correct specs; they are either out of stock OR, way too small for the terminal leads to be properly spaced ...any ideas or recommendations as to what you've been using? I've checked with Digikey as well but they seem to be in short supply as well. There are many with "screw" terminals - I could possibly modify the board to use these if necessary but wanted to acquire recommendations prior to taking that approach.
...any ideas or recommendations as to what you've been using? I've checked with Digikey as well but they seem to be in short supply as well. There are many with "screw" terminals - I could possibly modify the board to use these if necessary but wanted to acquire recommendations prior to taking that approach.
fernarias
Super Member
I have been using these: https://www.mouser.com/ProductDetai...0N183TC79M&utm_content=United Chemi-Con (UCC)
I like the price and I'm ok with drilling a hole on the pcb. They are the same radius but shorter but it causes no problems.
I like the price and I'm ok with drilling a hole on the pcb. They are the same radius but shorter but it causes no problems.
LFazio51
Active Member
Thanks for the Advice Fernarias. It's awesome to have such great advice on a project like this and I truly appreciate it.
I've looked at the Nichicon series as Avionic mentioned, but they are either out of stock or longer than 80mm which I believe will encroach onto the preamp/tone board when installed. Terminal spacing on ALL caps I've investigated is different and as indicated, will require modification regardless of what I go with; just happy to see others have encountered the same issues I'm facing. This has already caused me to consider modifications that will allow me a wider variety of filter caps to choose from. I'm $135 in the receiver as one of my first projects and was not really interested in spending $65+ dollars on capacitors given my lack of experience and the amount of work that's needed. I would feel a huge level of accomplishment if I'm able to get this puppy running properly again without investing another $100 in it. I'll do it if necessary but I'd rather not. I see where my filter cap options improve dramatically if I'm able to go with a "screw lug" terminal - I would simply need some additional guidance on modifying the pcb without destroying it. Below are some photos of the 1 cap I removed yesterday. slots in pcb are centered at 20mm. BTW - the cap I removed is reading 10.5kuf - the same reading my dmm gave me while still soldered in place.
Nope they will just fit.But you will need to modify the hold down bracket and either lengthen the lug slots in the circuit board or trim the lugs to fit. The last 1020 I did I used the Nichicon KG´s.
LFazio51
Active Member
So you're telling me the 100mm KG's will actually fit down there? DANG, looks extremely close to me but if you've done it, I believe it.
Let me pose this question to all - I've heard that super high grade filter caps are not really necessary since they are filtering supply power rather than signal. Is this true or false?
LFazio51
Active Member
Did you stay with the 63v or upgrade to the 80v? Just curious now since you've indicated 100mm will fit.
