Sanyo RP-7220 Schematic needed

[powerking]

All,

If someone has a copy of the schematic for this radio, I'd like to see it. It is ~~ 1972 vintage and covered the Am/Fm/Sw bands; with a front tuning meter and it ran on 4-C-cells. I need to replace the volume pot/switch and don't know the original resistance value of the thing.

Thanks,

Tom (PK)

[maxhifi]

Why not measure the existing one? Usually it doesn't fail open circuit.

[powerking]

This one has failed completely in the middle of the range and is a real P.I.T.A. to get to and approximate the value. It'd also just be good to have the schematic for reference when tearing the thing apart that if dummy (me) breaks any of gaggle of the period used Japanese jumper wires I know where the go.

Tom (PK)

[zeno]

Unfortunately not in Sams otherwise I would have it. Going to
be a challenge to find, only a Sanyo FSC may have had it.

73 Zeno

[zeno]

PS
They were usually well built & not much risk if you take it slow.
If it has a dead spot try a drop of WD40 first, just dont get it on the dial
cord ! It can work miracles.......
Another trick with pots with a dead spot is to add a resistor in
either series or parallel to move it off the dead spot.
Otherwise finding the right physical fit may be as hard as finding a
manual.

73 Zeno

[powerking]

I managed to measure the pot and it's ~~ 100Kohm w/switch. Problem is the rivet on one of the terminals isn't making contact to the carbon track.

Found this one on ePay from across the pond; wonder how many months it take to get it..

http://www.ebay.com/itm/120774177287...84.m1497.l2649

Tom (PK)

[NoPegs]

Originally Posted by powerking

I managed to measure the pot and it's ~~ 100Kohm w/switch. Problem is the rivet on one of the terminals isn't making contact to the carbon track.

Found this one on ePay from across the pond; wonder how many months it take to get it..

http://www.ebay.com/itm/120774177287...84.m1497.l2649

Tom (PK)

UK to US international usually doesn't take very long. Usually 3/4 of the Time-In-Transit happens once it clears US customs. Points for The Royal Mail, but not for USPS.


But realistically, you've gotten this far, and found the fault, so why not just fix it yourself?


You could just use conductive epoxy (think "circuit-writer pen") to fix it, maybe.

Actually, instead of spending money on a circuit-writer pen, grab one of these, same stuff...

http://www.amazon.com/Permatex-21351...efogger+repair

I think you're going to get the best price on A9, but if you have various auto parts stores along your normal travel paths it wouldn't hurt to stop in and see.

Loctite also makes a similar kit.

This is slightly better engineered stuff than the "conductive wire glue" that thinkgeek sells, that stuff won't hold up to defogger grid repair, but might hold up to your radio. The automotive stuff will hold up to your radio just fine, guaranteed.

[powerking]

At this point, replacing the entire control seems like the best option (since overall dimensionally it looks correct, but might have to chop ~~ 5mm off the shaft). Trying to take the pot apart to "rig" it might also end up in its destruction thereof. The problem with the pot is not just a broken copper circuit board trace type issue.

Tom (PK)