Tube Receiver Preamp Identifocation

[Harlon]

The attached images are of a Magnavox tuner/preamp from a 1ST622R console that I'm working my way through recapping and trying to refurb.

It came with a 9304-20 amp and 7001-20 MPX and a Micromatic TT I haven't identified yet.
The schematic I found somewhere online apparently misidentified the tuner as a 79-05-00 through 79-15-00. The console pictured on the sams is correct but the images of under the chassis and schematic don't seem to match.

Please take a look at the images and help identify.

Thanks

 

[Harlon]

Picture 3

 

[Harlon]

Picture two.

 

[Harlon]

Picture 5.

 

[Harlon]

Picture 4,

So I don't know my numbers in order and apparently my ipad doesn't have enough working memory to upload more than one picture at a time.

 

[Tom Bavis]

I'm seeing 59-37-10. I have a schematic for 59-00 through 59-11, that's the closest listing in Sams.

 

[gadget73]

yeah, 59-37-10 would be my vote as well.

 

[Harlon]

Nice I guess the 59-37-10 on the chassis should have given it away.

It's so far from what I expected I thought it couldn't be the chassis model.

Thanks, could you share a copy of the sams you have?

 

[Tom Bavis]

Schematic at least. Email tbavis(at)Rochester(dot)rr(dot)com

 

[Duce67us]

I just finished one of these!!
There is not a specific SAMS for this unit, but there is one that is close. It looks like Tom B. can send you the Schematic. I Used SAMS 655-10. The RCA's are not in the same place, and some parts are slightly different values, but it should be close enough to get you by.

Let me know if I can help.

One thing I will mention...
There is a cap, Black in color near the On/Off/Treble Control and pins 4, and 9 of the 6EU7 Preamp tube. The old cap has three legs.
It is in your pic. #5 in the upper left hand area. SAMS calls it C3 A and B
Just replace that with two caps.

 

[Harlon]

I just finished one of these!!
There is not a specific SAMS for this unit,

Let me know if I can help.

One thing I will mention...
There is a cap, Black in color near the On/Off/Treble Control and pins 4, and 9 of the 6EU7 Preamp tube. The old cap has three legs.
It is in your pic. #5 in the upper left hand area. SAMS calls it C3 A and B
Just replace that with two caps.

When going over the chassis, it looks like there are only four large caps, the black one you mentioned and the three white ones, plus the electrolytics in the can that need to be swapped. Was there anything else that you would recommend changing or upgrading while I'm in it?

Just as a note, other than an issue with the MPX, everything worked when I got. The unit was in a relative's home and has never been out of use since original purchase.

Thanks for the help, this unit is so layered and intricate I'm hesitant to cut into it unless I need to.

 

[Duce67us]

Harlon,
I can only give you my opinion, and what I did.

In my case, I bought a incomplete unit from a thrift shop, and my tuner was missing the 6EU7 Pre tube as well.

That being said, I can tell you that I replaced all the carbon resistors, favoring carbon film over the carbon comp. that were factory installed. I chose 5% 1/2 watt for my substitution parts.
The Large 3 watt carbon was changed to a 5watt Vishay/Dale wirewound, as well as the other two high wattage resistors in the power supply section.

Basically, the old carbon comp. resistors could be out of tolerance - if so, they should be changed too. I found roughly half of mine were more than 20% out, so they all were changed.

I did not have any adverse issues. IE. Alignment issues, poor tuning, etc.

 

[Harlon]

Duce67

You're a braver man than I. One look at that mess of resistors makes my knees quiver.

Thanks, looks like I'm going to be improving my soldering and third hand usage skills with this one. Lots of tight spaces.