amr2
Well-Known Member
I have not tested the sensitivity yet. I have a Onkyo T9090 to compare.
Picked up a non-working Yamaha t-85
- Thread starter amr2
- Start date
dr*audio
Fish fingers and custard!
The caps that go bad in the front end always seem to be the low value, 100pF and less. I have seen both coupling caps and impedance matching caps go bad. I did not test them, I went through the tuner and when the signal was good on the input side of a coupling cap and had too much loss on the output side, I replaced the cap. If that didn't fix it I replaced any impedance matching cap on the output side. A high impedance rf probe is mandatory for this. If you don't have that and a spectrum analyzer, I suggest replacing the coupling caps and low value caps to ground in the tuner. If that doesn't fix it, there may be a bad transistor. Most of the times it's the caps.
Ah, that I can manage. I was afraid you meant the 103z (.01) bypass caps, as there are 11 of those on the RF board and maybe 50+ in the rest of the unit. I need to see what's on the shelf for probes. I think I've got a high impedance Tek FET probe, but can't remember the specs. Probably just try some replacements and see if that helps.
edit- as I look more closely, there are only a couple caps that look critical, at least in the front end.
edit- as I look more closely, there are only a couple caps that look critical, at least in the front end.
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Forgive me if I'm wrong, but aren't those original caps already a form of supercap/goldcap? If you can find a replacement supercap/goldcap that has the original 10mm dia and can fit in a confined space without mods you will be the hero of many a '90s+ Yamaha amp (etc). I looked long and hard for something in that value for my CX-600 pre that was ca 10mm in diameter with no luck.
Cheers,
James
How about 10mm dia. X 20mm 4.7mf @ 5.5 vdc Nichicon's "JB" 85° ?
New !
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How about 10mm dia. X 20mm 4.7mf @ 5.5 vdc Nichicon's "JB" 85° ?
Iirc we discussed those caps a while back and you had bought a handfull of the last available. Do you mean that these are a new production? Do you have a link at Mouser? I'll be placing an order with Mouser for various stuff later today and will order some of those if they are available.
Cheers,
James
Yep. I found them about a week ago.
DRecovery
Pants-wearer
If you are truly married to a 10mm part "without mods," then you are likely more fanatical than the original designer. Myself, if it's mechanically stable, electrically stable, and production compatible then it's a go. And that's why I would stuff a gold electric double layer in there, as big as I could fit.
If you are truly married to a 10mm part "without mods," then you are likely more fanatical than the original designer. Myself, if it's mechanically stable, electrically stable, and production compatible then it's a go. And that's why I would stuff a gold electric double layer in there, as big as I could fit.
No, heh heh, one marriage is more than enough for me.
It's more a matter of space. I'm not afraid of getting creative to mount something, but if something can be found that fits in the ca 12-13mm available then that's the cat's meow. But the "as big as I could fit" part is the limiting thing. Cheers,
James
you mean the 12.5mm x 20mm won't fit?How about 10mm dia. X 20mm 4.7mf @ 5.5 vdc Nichicon's "JB" 85° ?
dr*audio
Fish fingers and custard!
This one is 11 mm. In stock at Digikey.
http://www.digikey.com/products/en/...=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25
The nice thing about Digikey is if you select USPS Parcel Post for shipping, it's usually $2 -$3.
http://www.digikey.com/products/en/...=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25
The nice thing about Digikey is if you select USPS Parcel Post for shipping, it's usually $2 -$3.
Ok,
Sidetrack question. I know next to nothing about super capacitors (except what i just read in Wikipedia). Please enlighten me. Why would that be beneficial to this particular application?
Sidetrack question. I know next to nothing about super capacitors (except what i just read in Wikipedia). Please enlighten me. Why would that be beneficial to this particular application?
They hold their charge for a very long time like a small battery (like many months if not years) without having to actually have a battery that can leak and cause corrosion. This charge lets the unit's small cpu hold it's settings memory.
Cheers,
James
Cheers,
James
Thanks for the explanation
To Germany ?
When I make an order for €50 or more with Mouser shipping is free. Fed-Ex Intl Express. Pretty good service actually. Orders usually arrive in 3 working days.
Cheers,
James
Cheers,
James
Thats a good deal . €50 is a typical order for me .It takes about 3-4 days for ground shipping and charge extra $8.
I've got my T-85 on the bench right now and am halfway through the alignment. Things seem better already, though it really wasn't too far out. The key might be entirely mechanical. Yamaha products often seem prone to bad solder joints and mechanical issues. I remember having to resolder the output jacks as they tended to go intermittent. While on the bench, I plugged in my antenna adapter that fits the odd one on the back of the T-85 and the center pin pushed right back in towards the chassis! Not a good thing if the antenna looks connected, but isn't! Easy enough to push back in, but I need to secure it with a drop of epoxy. I'll report back after the rest of the alignment is done.
