Classic Hifi Care

Hi everyone,
The local record shop referred this nice guy
to me with this 1962 RCA console with RS-199 amp.

I went to see it today, and it does have problems.
The owner said seller said there was some restoration.

No, nothing done since the factory.

I was not able to pull the amp to take home, but I did take the
RP-215 changer. It can be refurbed, no problem.

OK. This is what I observed today:

1.There is power to all tube filaments and pilot lights,
and record changer motor.

2. All wiring connections appear intact.

3. There is NO sound at all from the speakers.
Nothing.

Question:
I'm going to pull the amp at some point and
start the troubleshooting there.

What things should I look for that could
cause a complete lack of sound in the speakers ?

I have zero experience with radio circuits,
so I hope problem is w/in the amp.

Start with checking B+ at the positive terminals of the filter caps. I had a Motorola one time like that. The filter cap had shorted and it took out the rectifiers. If you have B+, then just follow the schematic on down the line until you find out where you don't have B+. Good luck.

Edit. I just saw where they used a wire as a fuse in the high-voltage side of the PT. I'll bet that's burnt in two. Again, check B+.

electra225 wrote: ↑Thu Aug 12, 2021 6:13 pm Start with checking B+ at the positive terminals of the filter caps. I had a Motorola one time like that. The filter cap had shorted and it took out the rectifiers. If you have B+, then just follow the schematic on down the line until you find out where you don't have B+. Good luck.

Edit. I just saw where they used a wire as a fuse in the high-voltage side of the PT. I'll bet that's burnt in two. Again, check B+.

Ok, very logical.

It will be interesting to see what that fuse wire looks like.
Why the heck didn't they use a glass fuse/holder ?

The very heavy console is staying at this guy's house, so
the amp will come to my house for work.

I would like to know what is a safe way to rig up a 120VAC power
supply to the amp so I can do the tests.

That amp has a power transformer, so it is safer to work on than a "hot chassis" would be without using an isolation transformer. If you don't have an isolation transformer and/or a Variac, that might be something for you to consider. Not only are these safety devices, to protect you from one side of the power line, but they are also useful diagnostic tools, as well.

According to the drawing, they used a 3" piece of #26 wire as a fuse. You should be able to find it fairly easily, I'd think. Fusing B+ is not all that common, particularly that late. I have an old 1928 Temple radio that has fused primary and fused B+. Very uncommon, but it sure would be hard to take out the PT with all that protection. I wonder why you couldn't eliminate the fuse that is there, and install one in the primary as is more common practice.

electra225 wrote: ↑Thu Aug 12, 2021 8:21 pm That amp has a power transformer, so it is safer to work on than a "hot chassis" would be without using an isolation transformer. If you don't have an isolation transformer and/or a Variac, that might be something for you to consider. Not only are these safety devices, to protect you from one side of the power line, but they are also useful diagnostic tools, as well.

I do have an original Variac that works well.

When I get the amp, I'll post some photos of the
inside.
Right now, I'm not sure what kind of wiring/connectors to
use to connect 120VAC on the primary of the PT.

From the schematic, and my view of the PT today,
there's only that 9 pin power socket to use.

The diagram shows a traditional power plug. ( oh, I see now what they are doing). Old age.....

You may have to remove the tuner chassis and use it to provide power to the amp chassis.

electra225 wrote: ↑Thu Aug 12, 2021 8:36 pm The diagram shows a traditional power plug. ( oh, I see now what they are doing). Old age.....
You may have to remove the tuner chassis and use it to provide power to the amp chassis.

Yes, I wanted to bypass that task. A friend with much more
experience than I, stated that without the tuner chassis,
the other tubes and transformer would be running a hotter
load.
So, I'll have to tank up on some Zen before I start that process.
But the owner is super nice, and he would really like the
RCA to be working.
I'll ease in to this, starting with the RP-215 changer.
Success with that will give me impetus to complete
the rest.

You could jumper the plug to the tuner. You won't have any controls for the amp. Those are in the tuner. The amp will run wide open. IT might be better to re-think not using the tuner. That is SOP when dealing with a Magnavox.

electra225 wrote: ↑Fri Aug 13, 2021 4:19 am You could jumper the plug to the tuner. You won't have any controls for the amp. Those are in the tuner. The amp will run wide open. IT might be better to re-think not using the tuner. That is SOP when dealing with a Magnavox.

That is a very good point, and I thank you for
bringing it to my attention.
I started on the RP-215 changer tonight, and it
was like meeting an old friend.
Funny thing I've never seen in one of these RCA changers,
there was a LOT of oxidation some of the aluminum parts.
It makes me wonder where this gal was stored and
for how long.

That may be some type of cadmium oxidation. PB Blaster is good for removing it and preventing it from coming back. Magnavox metal chassis are famous for this condition. Good luck.

The power transformer on the amp chassis has a 1:1 tap that provides power to the tuner chassis. The tuner chassis has the filaments wired in series like an AA5 radio, even has a 35W4 rectifier. I believe RCA did that to prevent hum. And the PT shields the tuner chassis from one side of the line, making it safer to work with. There doesn't appear to be any fuse protection for the tuner. You might consider fusing the primary of the PT. That will protect both the amp and the tuner.

That amplifier should not be too difficult but the tuner may disappoint. I have several RCA's of this vintage and those pre-FM stereo tuners seem so-so at best. The tuning eye is always cool but the reception is p***-poor on three I have tried so far. RC-1192 is a 61 and the RC-1205(A) is a 62. I even opened up the die-cast/German made tuner case and while it looks Identical to what Motorola used, I got nowhere close to a Moto's sensitivity and selectivity

I have found tuners from 63-on that use a 17C9/6C9 for the FM osc-mix are a huge improvement. I have two of those in my queue and the one in a console I sold was an RS-1205C, stereo version. That particular tuner was nearly as good as a Zenith!

No surprise the record changer is like working on an old buddy. Those were much easier to service than V-M and just a bit easier than same era Magnavox. May only need those three motor-board mount grommets, possible an idler wheel but not much more than a disassembly and cleaning that typically is it.

The pre-FM AFC Magnavox tuners are like that. They receive well, but they drift horrendously. You have to tune them three or four times until they get good and warm. They use a 6EA8 as an FM oscillator in the tuner. My experience is that the hated 6GH8A in place of the 6EA8 actually helps the drifting situation. The problem is that those old tuners without AFC have trouble demodulating the digital stereo composite they broadcast now. They don't know where the "middle" of the channel is, so they hunt from either side. The 6GH8A has a little better bandwidth, which may be the reason it helps. I see the RCA tuner uses a 6U8 in the tuner. Maybe a 6GH8A would help that tuner as well.....

Appreciate the input everyone.

I have finished the RP-215 changer, except for
sending in the idler to Gary at The V of Music.

I glued the old rubber tire back on the idler wheel,
to try a temporary record play.
That wood glue sure holds. The changer cycled
perfectly and shut-off.

The original RCA 110023 airplane style cartridge
has one bad channel, and the stylus bridge/yoke,
was hard and broken in the middle.

I found I had saved a Sonotone 8-T cart.
Both channels on it function, so I was to
use it.
The only difficulty was the RCA mounting
in the tonearm is 5/8 inch wide.
Most carts are 4/8 inch wide.
The mounting screw heads were wide enough to
catch the ends of the 8-T cartridge mount wings.

Sounds like you are making progress! That's a nice-looking changer.

That does look nice, you do nice work. Is the orange thing the old cartridge?

Bill

William wrote: ↑Sun Aug 15, 2021 1:32 pm That does look nice, you do nice work. Is the orange thing the old cartridge?

Bill

Bill, That is the cartridge and it uses the stylus that looks like an airplane. Only RCA used this...IIRC

I have a few carts like that and unless there is a broken/hardened bridge, they tend to work fine.
V-M has a sub but if the 8t is in good condition, I hope it can be used. Unfortunately most of my Sonotone carts have hardened wishbones (stylus-to-ceramic bridge) and I use a EV-5595

I have been using the EV-274 on older RCA changers like the RP-205, which has a compatible voltage output to the original.

Someday I hope to know more about cartridges and how to match them when the old ones are beyond use. Thanks Dave, and let us know how it all turns out.

Bill

Motorola minion wrote: ↑Sun Aug 15, 2021 2:11 pm

William wrote: ↑Sun Aug 15, 2021 1:32 pm That does look nice, you do nice work. Is the orange thing the old cartridge? Bill

Bill, That is the cartridge and it uses the stylus that looks like an airplane. Only RCA used this...IIRC

I have a few carts like that and unless there is a broken/hardened bridge, they tend to work fine.
V-M has a sub but if the 8t is in good condition, I hope it can be used. Unfortunately most of my Sonotone carts have hardened wishbones (stylus-to-ceramic bridge) and I use a EV-5595

I have been using the EV-274 on older RCA changers like the RP-205, which has a compatible voltage output to the original.

Thank you gents.

A big problem with the RCA setup, is that the 3 audio wires are
clamped down, so I only have about 3/8 inch of lead
length to use to connect to a cartridge.
There's a (I swear) riveted plate on the underside of the tonearm
that's hiding and holding the tonearm wire harness.

The Sonotone, fortunately, has both ground pins very
close to each other in the middle of the cart body.
So I slipped the ground wire connector over both pins.

And, yes, I'm VERY lucky this 8-T still has a pliable,
functioning bridge.
Most I've seen lose at least one channel, with age, too.

Wow ... nice job on the changer ... looks like brand new...