GE Console RC 7100 A - need some help! - diyAudio
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Old 9th August 2008, 04:21 AM   #1
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Default GE Console RC 7100 A - need some help!

I picked up this console out of a house I was living in, figuring one day I would get to fix it up. Here we are! I can't find anything about this particular model.

Click the image to open in full size.
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L to R - 12AX7, 6QA5A, 6QA5A, 6CA4

It was making a loud hum whenever I tried to turn it on, so I got new tubes for it. i know now that prob. all it needed was a recapping. I cannot figure out how to read this, tho:

Click the image to open in full size.

I can't figure out what the total voltage needs to be. Also, it has 4 wires coming out of it, a black (the common ground), a red, a blue, and a green. All the capacitors I have seen only have a positive and negative coming out. Can anyone help me on this?

P.S. If you know anything about the console that would be great too!
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Old 9th August 2008, 12:27 PM   #2
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It's a triple capacitor in one housing - you'll need three to replace it. The caps have 250 V, (more at initial power-up) so must be 350 V rating or higher. The RC7100 isn't listed, but it's probably similar to RC4640 shown here: http://techpreservation.dyndns.org/s...l_Electric.htm
(You'll need the DjVBu browser plug-in from lizardtech.com)
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Old 9th August 2008, 04:04 PM   #3
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Quote:
I picked up this console out of a house I was living in, figuring one day I would get to fix it up. Here we are! I can't find anything about this particular model.

Dude,

Whatever you tried to include in your initial post is not coming thru. If it's images, please provide URLs.

Notice that the RC4060A model Tom Bavis pointed you at has (IMO) yucky tone controls and uses a piezoelectric phono cartridge. If you use a CDP as the source and retain the OEM signal topology, less gain than a 12AX7 yields is needed. Replacing the 'X7 with a lower gain, but electrically similar, 12AY7 seems in order.

With very few exceptions, piezoelectric carts. literally scrub the HF info. out of record grooves. So, the OEM record playing stuff needs to be replaced.

You could do far, far, worse than switching to RH84 style circuitry. Replace the 1 MOhm resistors at the I/Ps with individual 100 KOhm log. taper Alpha Carbon controls from Mouser, to retain listening volume setting capability. ECC81 = 12AT7 and JJ (Slovakia) offers a decent version that's quite affordable.
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Old 11th August 2008, 03:13 PM   #4
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Sorry about the pics! I guess I have to attach them one at a time...the first one is the cabinet, then the record player, then the filter capacitor, and then the amp.

I ordered replacement caps the other day, so they should be in mid-week. I ordered a new needle as well, but you're saying that it's not worth it to keep it? I'm not a sooper audiophile guy...I just wanted to make it work.

That schematic looks very simliar to mine, but mine does not have a radio or a headphone jack. so here's another question: the switch on the record player turns the amp on. How do I need to wire it so the amp can be turned on with a switch? I am going to build a switchbox so I can use it for the record player and for an ipod or CD player. I've looked on the underside of the record player, but all I can see for a switch is a plate of metal that hits a little box that has wires coming out of it next to the motor. I have no idea what triggers it to switch off. Thanks for the help, and here's the pics.
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Old 11th August 2008, 03:13 PM   #5
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the record player
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Old 11th August 2008, 03:13 PM   #6
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the amp
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Old 12th August 2008, 12:50 AM   #7
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Quote:
I ordered a new needle as well, but you're saying that it's not worth it to keep it? I'm not a sooper audiophile guy...I just wanted to make it work.
Sorry, that TT is a POS. It might be OK for 78s and 45 RPM "singles". No way should nice LPs go on that groove killer. Look carefully at the "business end" of the tone arm. Do you see the little lever sticking out sideways? That lever gets flipped to swap between the 3 mil 78 stylus and the microgroove stylus. You can bank on the tracking force being several grams.

Quote:
How do I need to wire it so the amp can be turned on with a switch?
Remember the previous remarks about simplification and elimination of the nasty tone controls. There are 4 chassis openings for controls. Put individual L/R volume controls in 2 of those openings. Put an on/off toggle switch in yet another of the openings. Put a rotary source selector switch in the 4th opening. Mouser stock # 105-14572 is a nice, inexpensive, choice for the source selector. Mount several sets of RCA jacks in new holes that you drill.

Search the Mouser site and you'll find Alpha Carbon volume controls and the toggle switch you need
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Old 12th August 2008, 07:43 PM   #8
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Thanks Eli!

I found a Hitachi HT-354 from a guy on CL with a Grado cartridge...not a Cadillac, but much better than I had. I'll put the old one back in the console, and may/may not make it operational. Prob not worth the trouble.
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Old 12th August 2008, 11:24 PM   #9
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Quote:
I found a Hitachi HT-354 from a guy on CL with a Grado cartridge.

That's a significant improvement. However, you need a phono preamp that provides the gain and equalization the MM level Grado cart. requires to feed the console amp. Do you already own suitable electronics?
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Old 12th August 2008, 11:44 PM   #10
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Yeah, I can handle all that.

So, since I'm changing the pots (and moving them, bc the new TT won't go inside the console...I'm going to set up the power and selector switches and the new pots somewhere on the outside of the console)...all of them are dual pots. Why is that, and do I have to get dual pots to replace them? Also, take a look at that first pot on the left in the amp picture. On the amp, that's the "loudness" control. I cannot find a dual pot anywhere that had 6 poles on the bottom and the 2 extra ones those white and black wires are attached to. Do you see what I'm talking about? Do you have any idea what that does?
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