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 Post subject: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sat 20, 2018 10:01 pm 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
Can't wait to get this on the road again! I think I'm close. Here's a pic of the empty case:

Image

I have replaced the capacitors in the amplifier and left the resistors and selenium rectifier in place, as I believe they are good.

Image

I have also replaced the motor and idler wheel with spares. The platter spins at the correct speed!

However, I'm getting NO sound out of the speaker. I have verified the speaker is good. But I am a little confused as to the tone arm wiring ...

Is this correct?

Image

Just one screw for the ground as I see if I can get sound out of it ...

Image

Thanks in advance for any help here!

-Ryan


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sat 20, 2018 10:57 pm 
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Joined: Jan Wed 16, 2013 12:04 am
Posts: 1204
Location: 77001
1. The red lead appears to go to no amp connection on
the terminal strip.
I would assume it should attach onto the yellow
audio wire. Where does the yellow wire attach
on the amp ?

2. Have you tested the cartridge leads with your
finger at the cart for sound ?
That original cart may also be dead.
It is a crystal one.

3. At some point, would replace selenium rectifier.
Have you tested voltage after the rectifier ?
When they go bad, it's not a pretty picture.

4. Have you tested all resistors ?

5. Can you hear any sound at all from the
speaker ? Even if audio leads are wired
incorrectly, the amp should generate some
faint sound through speaker .

6. Are the tubes' heater filaments glowing ?

Report back with answers,
Hotwax


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sat 20, 2018 11:59 pm 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
Thank you! Answers to follow.

1. The red lead from the tone arm goes across a resistor (800k) to the yellow wire to the amplifier.

Image

The yellow wire attaches to the volume pot.

Image

2. I have tried 3 different cartridges and my fingers themselves across the leads, and no sound from anything. I am unsure which if any of the 3 cartridges are good, however. I am unsure how to test them.

3. Agreed, and I have diodes on hand. Maybe I should replace it - I am seeing 120V AC on both sides of it.

4. Just did again, and they are all good.

5. No, nothing at all. Before I wired the tone arm, it was producing a hum, but now nothing.

6. Yes, see pic, hard to tell but both glowing.

Image


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sun 21, 2018 12:06 am 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
I will say, I have a suspicion that this amp isn't wired quite like the wiring diagram I found for it. It all looks factory done, though, and I haven't traced it out, but still am suspicious.

Here's the diagram I'm looking at:

Image


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sun 21, 2018 12:57 am 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
Ok, well I replaced the Selenium Rectifier with a 1N4007 equivalent diode and am now seeing about 54V DC on the other side. However my 47 ohm resistor has decided to fail, and is now shorted out. Tubes are still lighting up. So I need to find myself a new resistor, the closest thing I have on hand is a 33 ohm 1/2 watt (think that would be OK?) until I can find a 47 ohm 5 watt ceramic.


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sun 21, 2018 1:12 am 
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Joined: Jan Wed 16, 2013 12:04 am
Posts: 1204
Location: 77001
Don't replace that 5 watt power resistor with a low wattage one.
The 1/2 watt might blow apart.


Once you have the proper power resistor, here's what
you can consider.
There were several versions of the RS152 chassis.
Attaching several sources of the diagrams.
(NOTE: Sams numbering for parts is different from
the Beitman's numbering)

If all the components looked original in yours, then go
with the values of those components, when replacing.

1. I would next suggest that you check voltage readings.

2. There could be a bad solder joint(s) in this 60 year
old player. Re-heating the joints is an idea.

3. You might check that the audio tube does not
have a short.
Also use some de-oxit on the 2 tubes' pins and put the
tubes back into sockets.
Don't spray deoxit directly on phenolic sockets, as
it can affect the plastic. Treat the tube pins as above.
Hotwax


Attachments:
RS152.jpg
RS152.jpg [ 151.64 KiB | Viewed 920 times ]
RS152-2.jpg
RS152-2.jpg [ 213.52 KiB | Viewed 920 times ]
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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sun 21, 2018 1:40 am 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
Thanks so much. Well, with the open resistor, I am not seeing much for voltage at the tubes - e.g., the 25L6 pins 3 and 4 are seeing under 1V DC.

I will be able to get a new 47 ohm 5 watt ceramic resistor locally in the coming week (place is closed Sundays - shoot). I'll report back once it goes in!

Thanks again for your help!


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sun 21, 2018 4:17 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 4057
Location: Boston, MA USA
There should be a black stamp on the chassis that indicates the amplifier model, RS-152x where x indicates the revision. Then use the correct schematic for that revision. It's probably RS-152D but maybe not!

The 47 ohm 5 watt resistor didn't open on its own, there is a short circuit someplace that caused it to overheat. Check your wiring carefully, especially the polarity of the electrolytic capacitors. If they are wrong they are ruined and you will have to replace them again. The photo shows a lot of bare leads on components that may contact something they shouldn't. You should re-do the wiring of the orange drop capacitors to tighten up the installation, using shrink tubing where necessary.

When you correct the short you can use a 33 ohm or 47 ohm 1/2 watt resistor. It's only there to limit the surge current to the rectifier, and was 1/2 watt originally. The 5 watt resistor was a replacement.

-David


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Jan Sun 21, 2018 5:49 pm 
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Joined: May Thu 14, 2015 4:15 pm
Posts: 746
Location: Dallas, TX
Something that you might do, especially if you are waiting to get a part is "yellow line" the schematic. This isn't a very complicated schematic so it should be pretty easy. On a copy of the schematic, using a yellow pencil to highlight, trace all the wiring and mark off the schematic as you go. That sometimes will reveal shorts, errors and modifications. You get to know the circuit better at least.

_________________
Tim
It's not the Destination, It's the Journey.


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Mar Sat 24, 2018 7:29 pm 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
Thanks everyone for the tips on the amp. Turns out everything is A-OK with the amp, and it was just the needle that was bad.

I have since moved onto the mechanical linkage underneath. As you can see from the above pics, this is an RP-190 record player. I took everything apart and re-lubed it all. The platter is spinning very nicely now, and the record dropping apparatus is working flawlessly. However I cannot get the cam wheel to engage underneath! I have 3 different cam wheels here and they all seem too small - they don't get close enough to touch the spinning gear underneath the platter, no matter how I have it adjusted.

Any ideas? I have tried a couple tricks - silicon RTV coating around one of them, thick plastidip around the second one, and they still don't get close enough.

Here's a picture for an idea of what I mean:

Image


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Mar Sun 25, 2018 4:34 pm 
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Joined: Mar Mon 24, 2014 5:19 pm
Posts: 1979
Location: Eugene, OR
Adjust the slider bracket to move the cam closer to the knurled wheel.

_________________
Handyman of the apocalypse


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Mar Mon 26, 2018 6:22 pm 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
Thanks - tried that, got it as close as it'll go. It *slightly* touches the wheel, but not enough to grab. It seems like the rubber on the cam wheel needs to be about 1/8" thicker.


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Mar Tue 27, 2018 1:05 am 
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Joined: Mar Mon 24, 2014 5:19 pm
Posts: 1979
Location: Eugene, OR
Johnny_Law wrote:
Thanks - tried that, got it as close as it'll go. It *slightly* touches the wheel, but not enough to grab. It seems like the rubber on the cam wheel needs to be about 1/8" thicker.

At this point either send your cam in to voice of music for resurfacing or buy one of the kits off eBay and do it yourself.

_________________
Handyman of the apocalypse


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Mar Tue 27, 2018 3:49 am 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
Squire wrote:
Johnny_Law wrote:
Thanks - tried that, got it as close as it'll go. It *slightly* touches the wheel, but not enough to grab. It seems like the rubber on the cam wheel needs to be about 1/8" thicker.

At this point either send your cam in to voice of music for resurfacing or buy one of the kits off eBay and do it yourself.


Ok thanks - I'll see what I can figure out!


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 Post subject: Re: RCA Victor Elvis 7-EP-45 - Help!
PostPosted: Apr Sat 14, 2018 9:21 pm 
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Joined: Jul Tue 18, 2017 4:30 am
Posts: 19
Image

https://youtu.be/E91yOQBVKB8


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