RCA turntable problem

Hi all,
I'm new to this forum, so this type of question may have already been answered, though I couldn't find it.

I have an RCA VHT-30W console stereo that has the RP-223 turntable. We're talking mid to late '60s here, idler, no belt. Anyway, the turntable seems to work fine on all speeds except 78 where it just doesn't have enough pull to keep the platter spinning consistently.

From what I've seen of this forum, there's a bunch of knowledgeable folks here, so I'm hoping someone can help me figure this out. Any help would be great.

Thanks,
Ken

Your idler wheel may not be putting enough pressure against the inside surface of the platter. The pivot joints may be gunked up and not pushing the wheel out completely, or your idler wheel could need some cleaning/rejuvenation and the inside of the platter cleaned. Also check the height of your wheel to make sure it lines up at the center positions of all the different sizes on the motor shaft. It may be adjustable. --BB


Bobby Basham
Tucson, Arizona

Asides from needing some maintenence due to aging, that changer's idler wheel may be hardening up or glazed... this will cause slipping.
You can attempt to rejuvenate it by removing it, noting how many washers are on the shaft (above/below the idler itself) and then use fine sandpaper or steel wool to cut the "shine" at the edge of the wheel.
Be careful though, you don't want to go too hard or damage the edge.... it needs to be perfectly round and smooth.... just without a shine.
Then use some alcohol to thoroughly clean it, the inside of the platter rim, and the stepped motor shaft.
Put a drop or two of lightweight oil on the idler shaft, motor shaft bearing, and if you can, the bottom motor bearing.
If the idler has hardened and not pliable (use a fingernail to press into the rubber edge), it'll need replacing.... it's too far gone.

As for the console electronics itself, if it hasn't been serviced, I'd get it done, because those RCA's are notorious for getting a hum which will eventually destroy the output transistors if used in that condition.
The germanium transistors used are available today, but rather expensive to replace.

lbaudio wrote:Hi all,
I'm new to this forum, so this type of question may have already been answered, though I couldn't find it.

I have an RCA VHT-30W console stereo that has the RP-223 turntable. We're talking mid to late '60s here, idler, no belt. Anyway, the turntable seems to work fine on all speeds except 78 where it just doesn't have enough pull to keep the platter spinning consistently.

From what I've seen of this forum, there's a bunch of knowledgeable folks here, so I'm hoping someone can help me figure this out. Any help would be great.

Thanks,
Ken

Matt,
I always think of "hum" as, "smoke --looking for a place to escape"-- Ron Rich

Ron Rich wrote:Matt,
I always think of "hum" as, "smoke --looking for a place to escape"-- Ron Rich

You're right Ron...
Hum, even subtle signs of it, can be disasterous if left unheeded.
Of course, single-ended tube equipment is mostly exempt from this.

What shivers me out is people continually using older equipment that hums badly... I feel so sorry for them when the End Nears....

Thanks for the replies. I had already done most of the things that are mentioned. I just checked the pliability of the idler and it seems to be fine though I can't say replacing it wouldn't make a difference. I did move some washers on the idler as I didn't like its position on the steps of the motor. This helped a little as the turntable will at least restart rotation after you stop it by hand. I'm a little confused that all of the speeds work fine except for the one. Being as the 78 speed is the biggest step on the motor, I would think that it should work the best, but it's quite the opposite. I did already recap the power supply, too.

Perhaps the idler arm spring needs replacing. Operating at 78 RPM the spring is to have greater tension whereas slower speeds require less tension...or something like that. I flunked physics. Other than that and what others have offered maybe the motor grommets. New ones will tighten up the whole shebang.
Bill

shedradios wrote:Perhaps the idler arm spring needs replacing. Operating at 78 RPM the spring is to have greater tension whereas slower speeds require less tension...or something like that. I flunked physics. Other than that and what others have offered maybe the motor grommets. New ones will tighten up the whole shebang.
Bill

Unless the tension spring has been damaged, it really doesn't need replacing.
The misconception of making it "tighter" to quell slippage is just that.... plain bull crap.
Due to the design of the assembly, proper "grip" is accomplished automatically, as long as the idler isn't glazed or hardened.

Additionally, if the motor mounts are too soft and deteriorating from age, it'll cause the motor to sag lower, naturally causing the idler to improperly seat on each "step".
RCA's, among others, are notorious for that. (topside, the motor grommets should appear as stiff tapered "cones" and not flat or deformed.)

lbaudio should check this..... shifting the idler by moving the thrust washers on the idler shaft to change it's working "height" is a "dirty fix" and only temporarily solves the problem.

Matt--
I agree 100 % with you ---I have seen "many" springs either "shortened", and or "elongated".
This NEVER solves any problems, for any length of time ! One must examine the problem, and find the "real reason" for the problem. Once that's done, it is magic--the spring was correct !!!
--in other words--Assume ( unless you see a "mangled" spring) that the problem is elsewhere ! Of course, all bets are off if some clown has changed the spring---
Ron Rich

As I've said it before in other postings....
My customers wouldn't want or expect a "backyard mechanic" repair.

You either do the job right, or get someone who can to do it.

I see a lot of "trading tips and nutjob fixes" online in various sites, and just shake my head.
It's like the blind, leading the blind.

Well, it looks like the 3 bushings for the motor/idler mount might be the problem. I'm assuming they would be rubber and these are very hard and crumbly. Thoughts? Any ideas where I can get replacements?

I'm just trying things...

lbaudio wrote:Well, it looks like the 3 bushings for the motor/idler mount might be the problem. I'm assuming they would be rubber and these are very hard and crumbly. Thoughts? Any ideas where I can get replacements?

I'm just trying things...

Try my friend Gary Stork at http://www.thevoiceofmusic.com/catalog/ ... mounts.asp

He's got them... the white rubber ones.

Thanks. I'll bet the new grommets will fix it up fine.

The "backyard mechanic"