Packard-Bell RPC-39 Solid State Stereo c. 1966

This forum is sparking a new hobby. A while ago I sold all my vinyl since I didn't have a record player. One day I found a Pioneer outfit at a yard sale and went home and hooked it up. I had my Beatle collection still, (I'll never sell that) so I put "Rubber Soul" on and was blown away by the sound. I had forgotten how awesome vinyle was. The popping and cracking that cd's lack just recharged my hunt to replace all the vinyle. Now, thanks to all your pictures, I want a console for my "Man-cave"

El Ramos wrote:Installed a pre-amp, and the turntable's volume and timbre now matches the other sources. The next, and hopefully final, restoration step is to replace the caps in the amplifier.

The originals are 1000uF & 500uF @ 50V. I have 1000uF caps, but 500uF-rated caps are proving hard to come by. Would 470uF caps be suitable replacements?

Do I need to replace the crossover caps as well? They're 25uF @ 25VDC, and seem to be non-polarized (both ends are marked with + signs.)

Finally, I'm having trouble finding a 45 adapter that works well. The LRS-6 won't drop records that are too thick, or have too little space between them when stacked. The LRS-20 tends to drop two at a time, and even dropped a record on the stylus while it was playing another one.

Thanks for any help...

30 uf difference is trivial... use them.

Don't blame the 45 adapter.... some records are just different.

Take my word if you can use 45 inserts use them. The 45 adapters were almost all trouble. I never found one I liked. I just got my mangavox working and thought there 45 adapter might be better I was wrong.

I'm familiar with both 45 adapters you're tried. I've never had a problem with the LRS-20 dropping two records, but I suppose it's certainly possible. You may want to consider the succesor to the LRS-20, the FLRS-35, which is available from Voice of Music Enthusiasts. This is one of the later, flat design adapters and I've had good luck with it. In fact, I just ordered one for a Garrard turntable I recently rebuilt.

One other possibility, although not readily available, is the predecessor to the LRS-20, the LRS-10. It's somewhat of a similar design; but the record "pusher wedge" is a different geometry. With the LRS-10 you have to remove the center post spindle for small hole records entirely, as the LRS-10 has the portion that inserts into the hole in the center of the platter. (With the LRS-20, the whole spindle comes out when you try to remove the adapter anyway.) I've never had a problem with the LRS-10 adapter either.

That is a Garrard AT-5. An LRS-25 also fits it. It has the slicer type spindle.

The saga continues...A few days ago I turned it on and heard a thin, loud buzzing sound on top of the music. Phono, Tape, FM, AM, makes no difference, the buzz is always there now.

I figured it might be the amplifier caps I'm about to replace, so I'm going to go for it. Question is, how do I replace a multiple-value cap with modern, discrete caps?

The legs of the old multi-cap are marked with triangle, square, and semi-circle shapes. How does this match up with the positive and negative leads of the two separate caps that will replace it?

The "can" portion of the old cap should be marked showing those symbols, and the value for each marking.
Those marked terminals (and sometimes an un-marked one) in the "center" of that can are all the positive leads.
The negative leads are the connections outside the circle,(usually connected to a metal can) and are common to all caps contained within the can.
Some (nice) companies show the symbols on the schemo's, also--others do not-- Ron Rich

The square, semicircle, and triangle match the markings on the side of the can, telling you the value of each capacitor.

Finally got around to replacing these caps. The originals were 1500uF and 500uF @ 50VDC. Having only 1000uF and 470uF parts, I paired them up and installed them in parallel to replace the 1500uF parts. Then, I tied all the negative leads together to ground as suggested. Powered it up, and...one of the replacements popped and "bled out." Oops. Looking closer at one of the original multi-caps, its triangle lead was labeled "common positive." Makes sense, since the the caps are buffering the positive and negative outputs of a bridge rectifier (see C10 and C11 in the attached diagram for how the parts are used in a sample amplifier circuit.)

Fortunately, I had spares. Installed them correctly this time, and everything's great! Buzzing is gone and the sound is no longer boomy/garbly. Really smooth, big frequency response. She sounds as good as she looks.

Thanks for the advice, everyone!

Am glad to hear it. Now sit back and enjoy.

After many months of producing good sound, the stereo has developed a warm 60Hz hum whose loudness increases the longer the stereo is left on. I've isolated the sound to the tube-based radio/pre-amp portion of the console (Other sources played through the solid-state amp are hum-free.) I really wanted to avoid getting into the tube portion of this stereo, but now it looks like I have no choice.

In addition to several tubes, the radio/pre-amp section has one large cap with four values:

• 40uF @ 350VDC
• 40uF @ 350VDC
• 20uF @ 350VDC
• 10uF @ 350VDC

I've already bought individual replacement caps. They weren't cheap! After doing some reading on tubes, however, it appears that this hum is a common symptom of bad amplifier tubes. Three 6BA6 tubes perform that function in this stereo.

I'm going to start by installing the caps listed above. If that doesn't kill the hum, it's time to shop for tubes. Does anyone have a source they'd like to recommend?

Sorry to resurrect an old thread but just wanted to follow up on my last post:

I finally replaced the big multi-value capacitor in my RPC-39's vacuum tube section with several discrete caps and this killed the hum completely. Finding the necessary parts was a challenge, though, since my usual sources (Digi-Key, Mouser etc.) don't carry caps rated at 350V. I eventually found them online at various different sellers.

I also acquired some spare used vacuum tubes but did not need to install them. The bass is still very boomy but I think that's just the nature of this amplifier and have decided to let it be.

You can bet the remaining old capacitors will eventually fail from age as well.
And that SS amp may not hum either - it'll just POP instantly, and you'll be replacing a lot more than capacitors then.

Electrolytic capacitors fail with age. Paper, mica, and mylar capacitors usually do not age.

Note that tubes do not cause hum unless they develop a heater to cathode short. This is a sudden loud hum when it happens.

Gotta dis-agree here--"paper" type do "age" ! Ron Rich