curious symptom old Fisher stereo amp, inputs strange

replaced it with an Onkyo. It's been so long I'd forgotten what was wrong .

junk pile and used it this weekend for a harpsichord at church.

nput that would work was Tape Out. It did not matter if monitor was on or off, or any mode selected.

ot worth fixing, I'm sure I got it for $3 at a yard sale, but I'm curious.

Not sure if you're describing this right as tape out is not an input. If t hat's the way it works, you definitely have a problem there. Try posting a model number. In any case, make sure it doesn't use pre amp in and pre a mp out jumpers (look like chrome horseshoes) that might be missing.

that's the way it works, you definitely have a problem there.

I'll look for the model tonight.

There are four sets of RCA sockets. REC IN, REC OUT, CD/AUX, Phono. I tri ed the input into all of them, only REC OUT worked. I know it's not an inp ut, at least I think it's not supposed to be. My vague memory says it used to work on CD/AUX and when one channel stopped working I just moved it ove r one set. Both channels worked on REC OUT.

While it's not worth a lot of effort to me, it is still the most convenient size amp I have when I need to carry it somewhere.

Sounds like you have a problem with the preamp section. Throw us a model nu mber.

In that Google search, it looks like the one on the upper left ? Black fron t ?

If it is what I think it is, it uses a TC91XX type IC for input selection, that coulsd be bad which would be bad because you know there are no new one s out there. Believe it or not I might have one. I have a couple of old one s that vintage. One is not coming apart becaause it only has the typica blo wn channel, but there is another one might have it that is scrap.

It frequently does work to backfeed it through the tape output. It's not ex actly the right way to do it but it works, though on some moels with some s ources you get higher distortion because you are impressing the signal on a n output. However, it shouldn't hurt anyrthing doing it that way.

Never knew that, thanks.

So, that amp, it has tact switches and lights that tell you what source it is on ?

If they are mechanical switches, actually that is good. that means likely a simple problem. If it is electronic, you might neeed that chip.

If it is tact (not mechanical) switches, do the lights light up to indicate the selected source ? If so that is bad. If they don't light up irt is pro bably a power supply problem and a 2SD613 might fix you up with a 12 volt r egulator or something. If the chip, WELLLLLLLL, there are solutions of one cannot be had.

Still, get that model number in here and we'll know all about it in short o rder.

If the switch was a mecanical rotary switch, the inputs would go to the separate pins on the switch, and the selected input would then be connected to the viper and the tape out, and further through the volume and tone controls to the output stage.

So the switch, whether mecanical or electronic, is dead, and you are feeding the signal directly into the volume/tone controls.

If you don't need the other inputs, I would just cut my losses and the connection to the switch, and just feed into the tape out, obviously the tape out is not buffered, otherwise you would be trying to feed signal backwards into an amplifier, which would not work.

A HiFi-nut would probably replace the switch with goldplated reed relays anyway :-)

Leif

On some receivers/amps, the "Tape Out" RCAs were where you connected the output FROM the cassette/tape deck - to hear it back. Counter-intuitive, and took me time to figger out! :)

Okay, this is a Fisher CA-400.

It has 5 sets of L and R RCAs on the back. They are marked Phono, Tuner, C D-Aux, REC OUT Tape, P.B. Tape. The only one that seems to work is REC OUT .

On the front there are 4 pushbuttons, for Phono, Tuner, CD-Aux, and Tape Mo nitor. All the buttons push in and lock, but no indicator lights of any ki nd appear anywhere. The power indicator light does come on.

It says 250 Watts on the back. It's a compact unit, the sound was not too bad out of it, even driving some home entertainment speakers. It would be nice if it worked. But if repair is more than a parts swap it will be beyo nd me. In my youth I held an Amateur Extra Class (NX9L) and I did some pro jects, but those days are far behind.

I can't seem to get a print for that unit but from what you wrote I owuld bet you have a 12 volt regulator out.

If it has mechanical switches, you say the "lock" in, then it does not use that unobtainium IC. It might use some 4066 type CMOS switches but those are easy to get. But the fact there are lights not lighting means likely a supply is missing.

bet you have a 12 volt regulator out.

e that unobtainium IC. It might use some 4066 type CMOS switches but those are easy to get. But the fact there are lights not lighting means likely a supply is missing.

There are also a couple of weird outlets near the speaker terminals that ap pear to supply voltage to components.

I was going to throw this thing away. But if you think it's safe to use pu tting the input into the output sockets, maybe it is useful as is. (I mean safe as in not failing when I need it most in public.)

My memory is not reliable but I think I used it as a home stereo amplifying my laptop and feeding a couple of regular stereo speakers. And when one c hannel stopped working I moved the inputs over one, not realizing I was usi ng an output, and it worked again.

Yes, the perhiperahls ere not stand alone. Some called these rak suystems, I called them frack systems for "fake rack". But the amps did have juice. W hatever of these are left, the perips are usually gone but the amp remaians , maininly because it was nevr bat on propoerly, overheated ad fried out. F isher did alot of shitty shit back then. Some units were OK though, for exa mple my garage stereo is a CA-885. Don't borher looking it upo there is alm ost zero info on it. It is close to 200 WPC and just doesn't care. In fact it puts out over 200 WPC bu I havn't tried to measure it accurately. All I know is it ran the lathe off the speaker wires just fine. (JK)

Those outlets are usually aboiut 12 V AC or so. Yuo DO NOT have to use thei r particular perips, anything that pliugs in the wall wil work as long as y ou got cables to hook up thre audio signal. You can ru that amop with amnyt hing, it is just the juk they sold with it is dependent upon that amp for a power source. It does not work both ways.

Bnottom linee, I bet you smack that thing hard on the fround it works. And I bet you find bad connections on a three terminal device that says sometin g like "7812" on it.

Tape out is an output, not an input. I have an older unit. It's for putting the output to a tape recorder.

Evan, Here is my setup. My HP laptop feeds an M-Audio Fast Track external sound card/USB interface. RCA cables out of the M-Audio feed the Tape Out of the Fisher amplifier. Plenty of loud sound comes out of the speakers.

I have also tried this with the Fast Track feeding an Input on a Pioneer amplifier. Loud sound comes out of the speakers this way too.

Very clearly, the RCA sockets marked Output on the Fisher are functioning as an input. Also clearly, the sockets marked Inputs on the Fisher don't do anything.

Something is broken. Or, maybe outputs always work as inputs and I just never tried, I dunno.

The tape out jack is essentially a fixed level audio out that comes from th e switching IC. If the IC is defective, you are likely backfeeding the IC from the output into the amp. Replace the switching IC. This is likely to be a TC9163 or an LAxxxx (I don't recall the number).

Dan

Been through that. The indicator lights are not lighting but the buttons are "locking" in. That means no TC9164. Or 3, or whatever.

Evan Platt forklarede:

Tape output is connected to the connection between the input selector and the volume/tone controls.

If there is no buffering on the output, it will also function as an input, feeding signal to the volume/tone controls.

Leif

So is there any harm in just running it that way and using it?

Paying for the manual would be alright if I was working on it here. But for someone on the web at random, no. Can't do that.

Thanks anyway. Maybe the OP wants it though.

Interesting that is an OEM manual they say. Usually they generated their own. Are they like a licensed reseller or something now ? they used to reverse engineer almost everything, but I know that has gotten more difficult by orders of magnitude.