[garyh1]

I have aquired a 201x high fidelity console radio. The power transformer has been replaced with a non original model and I would like put it back to original. Here in lies the problem, the only original transformer I have been able to locate is a part number 32-7259n which I believe is a 25 cycle unit. Will it work ?

[garyh1]

I found previous discussions in the forum that indicate that it is risky do to high b+ voltage concerns.Sounds like I should keep looking for a 60 cycle transformer. Thank Gary

[Radioroslyn]

If having too high voltages on the secondary is your concern then why not use a bucking transformer to reduce primary voltage? A 12v or 24v job could knock your line voltage down to 113 or 111v.
http://www.allaboutcircuits.com/vol_2/chpt_9/5.html
Good luck
Terry

[Alan Douglas]

Where is this previous discussion? I can't see any reason why a 25Hz transformer won't work. Yes it may have better regulation, keeping the secondary voltages higher under load, but this hardly seems like a defect. As already noted, if your line voltage is high, run the set from a bucking transformer to reduce it by 6 or 12 Volts.

Nice radio by the way. Some years back I borrowed one for side-by-side comparison with my Stromberg-Carlson with the acoustic labyrinth. The 201X sounded noticeably better.

[garyh1]

Thanks for the information. I think I will go ahead with the 25 cycle plan. I am also curious if anybody out there has replaced the electrolytics in one of these. there are 4 small value caps housed together , three ones and a two. Should these be replaced. I really like this old radio and am looking foward to making it perform as it should. Thanks, Gary

[codefox1]

Absolutely replace all the electrolytics, and every other capacitor in the set before you fire it up. Otherwise you will be looking for yet another power transformer.

[garyh1]

The schematic doesn't show + or -, should I assume all - go to ground.

[codefox1]

Assume nothing. Please post the schematic you are working with, or at least a link to it. There may be one capacitor wired just the opposite to supply a bias on the output circuit. I am not familiar with this set, but since it has a power transformer, logically all the smoothing capacitors would usually return their negative to the chassis ground. This is not always 100% true, so please wait until someone else chimes in. You will have a little time on your hands anyway digging out the tar and foil and crap from that can before you stuff it with modern components. There's little to no chance that those components are any good or safe after all those decades. Proceed with caution. And all that garbage you do dig out is pretty nasty, so do a proper disposal and cleanup of yourself and your bench.

Keep us posted.

[garyh1]

I don't have any caps of the correct value on hand so I will need to order them. This should allow plenty of time for others to respond. Thanks for your input. Gary

[Radioroslyn]

On this set most of the filters sit at 250ohms above the chaiss.
Terry

[Ron Ramirez]

Hi Gary

Great acquisition!

In regard to part (29), which is 1, 1, 1 and 2 uF in one can, the negative leads of all four of these do go to chassis ground. And, yes, these absolutely must be replaced if you are going to use the radio. As codefox has previously stated, you need to replace all paper and electrolytic capacitors in the set. Also check the resistors, and replace those found to be more than 20% higher or lower than stated values.

The main power supply filters, (101) and (102) were originally 8 uF - replace with 10 uF, 450 volts or even 500 volts if you can find them. The B+ at the input filter is greater than 400 volts DC. The negative leads of these need to connect to B-, the same place as the center tap of the high voltage secondary on your power transformer. Positive leads need to connect to either side of the filter choke (99).

A word about the other (101) in the circuit, the 10 uF cap connected between B- and ground. This one is 10 uF, 50 volts - and the POSITIVE lead needs to connect to ground. The negative connects to B-.

[garyh1]

Ron, When I bought this set the two eights and the ten had been replaced along with the power transformer. The four and the three ones and the two appear to be original. The first thing I did was to restuff all the bakelites and and replace all other paper caps. The radio plays and sounds ok but the transformer voltages don't seem correct. About 100 volts low across the plates of the rectifier, filiment voltage on the rectifier is ok but the filiment voltage to the remaining tubes is 5.9vlts. Is that to low ? As I mentioned before I would like to replace the non original transformer with an original, and the only one I could find is a 25 cycle unit. I will take everyone's advice and replace the remainder of the electrlytics and then tackle the transformer issue. Its nice to know that you have been into one of these before. Your advice as well as all others is greatly apprieciated. Gary

[Ron Ramirez]

I've never worked on a 201X, but I have restored a 200X.

I strongly suggest you take Alan's advice and install the 25 cycle power transformer. It will run happily at 60 cycles.

Edit: Part no. 32-7259 is the correct (25 cycle) power transformer for Model 201X.

[garyh1]

I believe the alignment procedure is equally as complicated on the 200x as it is on the 201. I am sure I will need to tap your expertise when that time comes. Thanks much. Gary