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RCA 4VF464 Restoration

jheu02

jheu02

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My first tube project. Got this console at GW for $25. I don't know at this point whether I'll try and restore the pre/tuner right now as I'm mainly interested in the RS-177J amplifier. Part of me says to go ahead and restore the whole thing. We'll see.

Here's some pics. Any help on this will be greatly appreciated.

The console as is:
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RS-177J...lots of cleaning to do.
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Exposed...lots of room for mounting new caps.
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Tubes detail...All look original. Any problems? Can I go with 47uF vs the 35uF?
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Funky 6-lead things. What are they?
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Detail under the OPTs. Are the small ceramic(?) discs the "death" caps?
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One side's speakers and a reason why I might redo the whole console.
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Here's a quick feasibility question for this restoration. It looks like the tuner/preamp gets all it's power from the main transformer on the amp portion via the Molex umblical. Since I may want to restore the whole console, is it ok to just wrap the amp's Molex in electrical tape for future use, leaving all the wires connected to it?

I realize I would still need to wire in a power switch to use it as a standalone, and if I DO decide to restore the pre/tuner, I'd then have to leave that switch "on" all the time and control power with the original switch. But is it doable, or is there an issue with leaving the Molex wired up inside the amp, but not connected to the preamp?
 
Pics of the RC-1211A Preamp/Tuner

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Pretty nice build quality. Besides the large can, only 3 electrolytic caps. 3-gang AM tuning cap, but not sure how many FM gangs as it's all shielded. More to come once I get my replacement caps.
 
Unfortunately yur not going to get many people who've experience on THAT unit.
And That amp needs all it's caps and resistors "replaced", and I mean all of them.

(not to be bearer of bad news, just my opinion, but..)
If your not familiar with working on these it's probably to much a project to tackle.
(If your seasoned in repair and or just feel ambitious dive in) :)
 
Thanks. I've already got the schematic and djvu reader. Been studying it and comparing to the actual wiring, resistance readings etc. Just placed my order today for new caps, resistors, fuse holder, etc. 2 Questions:

What's the best way to deal with the Molex connector if I decide to make this a standalone amp in the future?

Can the feedback circuit (wire loops outside the chassis) be moved inside or is there some reason it sticks through the chassis on those 3-prong mounting connectors?
 
jheu02 said:
Thanks. I've already got the schematic and djvu reader. Been studying it and comparing to the actual wiring, resistance readings etc. Just placed my order today for new caps, resistors, fuse holder, etc. 2 Questions:

What's the best way to deal with the Molex connector if I decide to make this a standalone amp in the future?

Can the feedback circuit (wire loops outside the chassis) be moved inside or is there some reason it sticks through the chassis on those 3-prong mounting connectors?
Click to expand...

If you might need it in the future, just leave the Molex connector as-is. You WILL have to add a jumper to power it up. The red jumper plugs are removed to connect external speakers, I suppose...
 
Tom Bavis said:
If you might need it in the future, just leave the Molex connector as-is. You WILL have to add a jumper to power it up. The red jumper plugs are removed to connect external speakers, I suppose...
Click to expand...

Tom,

Ahh...I hadn't thought of it having an option for additional speakers. So, they can be removed and just wired internally. My plan if I make it standalone is to build a nice wood trim around 3 sides like I've seen from others' builds. Those jumpers would get in the way of a tight fit unless I remove them or drill an indentation in the wood to make room for them

Just want to make sure I'm reading this right. How's this look for where the jumper would go (blue jumper, red the "hot" line, black the neutral)?

7043775343_e96acc69a7_c.jpg



Once jumped, the amp would be always on once plugged in correct? What would be the best way of implementing a fuse and power switch? I'm thinking of moving the power cord to the opposite side of the amp and adding binding posts and RCA inputs as shown below. Are there any considerations with this layout and the positioning of wires due to where the rectifier tube is located and/or the replacement eletrolytics? With all that space in the chassis, I see no need to restuff the cans.

7043876815_b2e70cc8c6_c.jpg


Got to love Mouser (no affiliation). I placed my order around 1pm today and I got the "shipped" confirmation earlier this evening. I should get everything on Friday! I also ordered a bunch of extra stuff to do a partial recap of a KT-815, the caps in the Pre/Tuner of this console, and replace the cans in my Fisher 400c (I may have to restuff some in that due to a crowded chassis).
 
Small Bump in the Road

While desoldering the 6-leg multi-resistors (since I'll be doing some rewiring and using new individual components) two of the pin solder-tabs (one on each socket) broke off. I imagine I'll need to completely replace those sockets since it doesn't look like you can replace single pins.

I'm going to place an order through PE as I have some other things I need to get anyway. So, other than making sure the new socket fits the punchout, are there any favorite materials (ceramic, micalex,other?) that I should be looking at?

The the 6FQ7 sockets are 9 pin. The 6BQ5's are 9 pin also. Will these work for both if I break any others? Or should I just go ahead and replace them all since there's only the 6 tubes? Thoughts?

And for mounting...since I'll have to drill-out the original rivets, just use small bolts, nuts and lock washers?
 
You could use those sockets, but there top mount, and you'll probably need to
widen the hole somewhat to get them in. (but they'll be secure an work well)

The originals are bottom mount, and when looking those type replacements you
can tell by looking at them the mounting bracket will be very very close to flush
with the top. (and will more then likely say bottom mount)

Now about replacing all of them, certainly wouldn't hurt, but those brown wafer
ones should pretty much always be replaced as you'll probably break them all up.

And yep with the:
"drill-out the original rivets, just use small bolts, nuts and lock washers"
 
As to your wiring of the jumper yah that looks good, and I to would put a fuse
an power switch on it. They can go in either AC line feeding the power tranny.

Also locations of the power cord, fuse, inputs, binding posts, looks good to me.
 
I've done a couple of those amp chassis, (different models) an see the holes
over by the reciter and front bottom edge of the power tranny? you'll see an
nut slightly covering one hole if you move up a bit there's another hole, what
I've done is use that to put one of the small power switches in without work.

That hole works great for one of those nice small power switches.
 
Hiya,

Those multi legged things are not "just resistors" and contain other components like capacitors. They are called "PEC's" and denoted in the schematic with a box drawn around the circuitry inside. Usually a few resistors and caps in each. You can make new ones with a little piece of bread board if you think they are a trouble spot as there is no real way to test functionality external on them.

Frannie
 
buglegirl said:
Hiya,

Those multi legged things are not "just resistors" and contain other components like capacitors. They are called "PEC's" and denoted in the schematic with a box drawn around the circuitry inside. Usually a few resistors and caps in each. You can make new ones with a little piece of bread board if you think they are a trouble spot as there is no real way to test functionality external on them.

Frannie
Click to expand...

I have pecs like Gregory Peck.:D

I like the idea of rebuilding them as I would be willing to bet they have trash components inside and could even be electrically leaky. I don't know what the brown casing is, but over the years I imagine it could have drawn moisture depending where and how the amp was stored. Heck, if the stock boards in a PAS can be leaky, I'd think these could too.:scratch2:
 
Hey Frannie, have you ever seen those little resistor networks for printed circuits that have several legs sticking out that allow you to make about any value you want? Maybe that's where the confusion came from. Those things are pretty cool, but fairly worthless for us point to point folks.
 
Jay,

Spot on .. And yep on those multi legged resistance things. You see them terminating SCSI disk daisy chains for example.

And the fact is there really is no way to test these things functionality.

So I consider it a best practice to replace them when I see them. Some others differ on that for various reasons. Maybe the best compromise is to build new ones if the area they are installed is even remotely suspected to be degraded.

Frannie
 
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While I'm at it, that has to be the most tired looking pair of 6BQ5s on the planet. They did their job and then some. Must have been a decent design.
 
buglegirl said:
Hiya,

Those multi legged things are not "just resistors" and contain other components like capacitors. They are called "PEC's" and denoted in the schematic with a box drawn around the circuitry inside. Usually a few resistors and caps in each. You can make new ones with a little piece of bread board if you think they are a trouble spot as there is no real way to test functionality external on them.

Frannie
Click to expand...

Well, that's the thing, I just have the schematic for the "H" version, not the "J." There's no paralleled caps listed on the "H" schematic, yet all the other "downstream" resistors, etc are the same values in my amp as listed on the schematic. If you have the specs from the box, or the actual "J" schematic that would be great. Otherwise, if I can't get the specs, I suppose this rebuild will make it revert to the "H" specs.
 
jaymanaa said:
While I'm at it, that has to be the most tired looking pair of 6BQ5s on the planet. They did their job and then some. Must have been a decent design.
Click to expand...

So, you're saying I probably will be needing some new tubes also. :scratch2:
 
Very nice RCA console, was made in 63 64 . It was close to 900 new it was one of the better ones they made. Had the nice studio Matic changer in it. If you go on YouTube type in RCA console stereo. I own the same one:) you can see and hear mine play. I have mine in our office at the house.
I had mine fully restored the end of last year. I was fortunate with mine as it was in the same house same owner since new so it was very clean and like new.
I hope you get this unit fully restored you will enjoy it a lot, has huge sound and sounds great. Glad you rescued it!
 
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