RCA Scholastic classroom record player - Videokarma.org TV - Video

radiotvnut · #1 03-13-2015, 12:09 PM

Here's one you don't see too often - an RCA Scholastic 4-speed tube classroom record player from 1965. This one uses a series string chassis (35W4, 50C5, and 12AV6) and will need the usual mechanical and electronic overhaul. Even though it's from '65, it still has some wax capacitors in it. I thought these were pretty much gone by the mid '60's; but, I guess RCA was still using them. During my school years, I don't ever recall seeing an RCA classroom record player. The city school district had Califones (or, that's all I ever saw). About 20 years ago, someone I know bought a bunch of junk from the county school and I ended up with some of the record players that they had. Those were a mix of Audiotronics, Califone, Newcomb, and VM.

maxhifi · #2 03-13-2015, 12:12 PM

Is that a BSR mechanism? I'd like to see an internal photo! Got to love that great big RCA logo on the front, could almost confuse it with some of their good stuff
-Max

radiotvnut · #3 03-13-2015, 12:56 PM

It's a General Industries mechanism. They offered that same basic mechanism with the knob speed selector for 30+ years.

maxhifi · #4 03-13-2015, 01:10 PM

Oh yeah, just like the one Califone used. I got that confused somehow!

radiotvnut · #5 03-13-2015, 04:58 PM

Here's the inside of the amp with the cover removed, before repairs, and the schematic.

rca2000 · #6 03-13-2015, 06:55 PM

Would NOT exactly classify that as a "sexy amp", not like it would be--if it had one or two 6BQ5's 6AQ5's 6V6's or even 6L6's...but it is "typical" of a hot chassis record player amp of the time frame.

maxhifi · #7 03-13-2015, 08:01 PM

I don't know, it has a "bumble bee" cap, like many things Old and RCA, it has a hum bucking winding on the output trabsformer and is fully shielded. Plus it has real RCA tubes, and has a 12AV6 instead of a crummy lone 25EH5. The output tube had a bypassed cathode, and the motor even has a plug and socket instead of being hard wired. It also has a real can for the filter capacitor instead of one of those cheapskate cardboard multi section caps. I would say I like this record player a lot, it's a nice one. I wonder what it has speaker wise.

rca2000 · #8 03-13-2015, 08:13 PM

25EH5 (Or ANY of the "eh5 line)has to be about the WORST amp tube EVER !!

maxhifi · #9 03-13-2015, 08:21 PM

Quote:

Originally Posted by rca2000

25EH5 (Or ANY of the "eh5 line)has to be about the WORST amp tube EVER !!

Not if you're a 1960s bean counter! Pair of 50EH5 was all you needed for a stereo amp. What I never understood are the Japanese radios like my Sanyo mini console which use 50EH5s with preamp tubes - Why on earth someone would trade the power of a 50C5 for gain they don't need makes no sense to me.

radiotvnut · #10 03-13-2015, 08:46 PM

The speaker looks to be a 5" or 6". I have it all recapped, mechanism cleaned, and working. Sound wise, it's not as good as some of the better classroom record players; but, I've certainly heard worse.

There's one issue with this unit that I've seen on many other single play models. As most of you know, the motor shaft is stepped for the 4 different speeds. The top portion that's the smallest is for 16 rpm, the next section down is for 44, followed by 45, and the last section that's the biggest is for 78. The small 16 rpm top section is bent and I've seen other manual players where the 16 rpm section was either bent or broken off. Fortunately, the only 16 rpm records that I own are talking books for the blind and I have machines that will play those. However, I would like to know how so many of these end up having the 16 rpm section damaged.

maxhifi · #11 03-13-2015, 10:46 PM

How much clearance between the underside of the turntable and the top of
The shaft? Or maybe it touches and bangs around if the player is dropped upside down? Would the motor then be supported by the shaft resting on the edge of the platter of
The grommets are loose?

Just some
Theories

dieseljeep · #12 03-15-2015, 11:16 AM

Quote:

Originally Posted by maxhifi

I don't know, it has a "bumble bee" cap, like many things Old and RCA, it has a hum bucking winding on the output trabsformer and is fully shielded. Plus it has real RCA tubes, and has a 12AV6 instead of a crummy lone 25EH5. The output tube had a bypassed cathode, and the motor even has a plug and socket instead of being hard wired. It also has a real can for the filter capacitor instead of one of those cheapskate cardboard multi section caps. I would say I like this record player a lot, it's a nice one. I wonder what it has speaker wise.

It looks like a feedback winding to me. The humbucking winding is usually part of the primary. If you look carefully at the electrolytic, you'll see a cardboard tube type in a twistlock can. They seemed to do that, a lot in portable phonos.
I don't think, RCA built it. The schematic artwork looks the same as the schematic, that came with my one tube Decca. It was built under contract.
They seemed to do that a lot in their special products line.

radiotvnut · #13 03-18-2015, 09:24 PM

I performed a few modifications to make this thing perform a little better. First, notice that the cartridge shunt resistor is a 270 Kohm; which, seems a little low for this application. A friend, who follows my post, saw the schematic and also told me that he thought it was a little low. I replaced that resistor with a 1.5 megohm and it now has better tonal quality and more volume. The chassis isolation capacitor was originally .068 uf. I replaced it with a .015 uf AC safety capacitor. Lastly, I dug out a junk kiddie player with a good rotor; so, now we have 16 rpm again. Those old beat up kiddie record players that I've brought home over the years often are a valuable source for parts.