If it is not back biased it will have more parts as every valve other than the rectifier will have a cathode resistor and the one for EL3NG will be around 150 Ohms and 6V6 around 270 Ohms.

I would go further with the Electrolytic's; Working volts & Peak volts as well. That may give a clue to B+

If you run 5Y3 sideways you risk destroying it: Absolute no no; there is only one horizontal position where that can be done.

It does look close to this one;

http://www.radiomuseum.org/r/scharnberg_model_41_ech35.html.

There is nothing to suggest it had the valves in the right order or was a worker.

Marc

The blue set in the above link is from my collection and the valves are in the right holes. The difference is that mine uses a 5Y3G and a 6V6GT, whereas in Steve's set, the 5Y3 is a GT type and the output valve is a G type.
This is probably the reason Steve tried swapping them, ref post#7. I can guarantee mine is a worker
Harold

The two lower caps are marked "8MFD 600P.V" I'm assuming these are 8μF 600volt. The next larger one up is marked "10MFD 40P.V" all the others as you can see are marked .05 varying from 400 to 200v. I guess these can be replaced by 47μF caps say 450v? One is marked .005.

The plan at this stage is to replace the caps and see how it goes. I've not done a set in such bad condition! That's why I like plastic case radios......

Do you guys think it's worth doing?

Steve

Do you guys think it's worth doing?

It's not a set I'd bother with unless it was rare and had nostalgic value to me. Otherwise, too much effort. There are much easier, and well documented, sets to be found for restoration.

With the amount of corrosion, if you want it to look anything like pristine, you are going to have to strip the chassis and that will not take 5 minutes, nor will reassembly.

Now. If you want to get it going & just kill the rust with a bit of CRC, WD40 etc. Just buy 630V caps to replace all of the wax paper type. Check the resistors as you go, the grid resistors on the OP tube are for some reason rarely in spec.10% out is my limit. 1Watt replacement resistors, unless circuit demands more (or is wire wound, which rarely fail).

You cannot use 450V and you cannot go that big. The limit on 5Y3 is a total of 32 mfd. Note the surge volts on the caps. For the HV filters 10μF and the reason they used 600V is because of the start surge. I will never go below 500V with 80/ 5Y3 if the set is designed for a 250VDC B+. Modern caps rarely have surge voltage on them.

For the cathode bypass 10μF 63V is now a common value & I often use RB type as you can mount it on the socket (but not with the leads short...heat)

The value of the cathode resistor of the OP valve, can give an idea of the plate voltage of the valve.

What is not mentioned with that set is that as it only has four valves, so is likely reflexed. So the EBF35 will be handling DC RF & Audio, which causes some digital voltmeters considerable grief.

I did pass comment on what I thought of the musical valves exercise.

Marc

Ok thanks Marc. I think I'll just fix the cabinet and get the set to work as best as I can. I don't get a good reading on the large valve on the valve tester, but I'm using EL33 settings. The 5YGT rectifier looks good the 6A8G measures good and the EBF35 is good as well. I'll make a start on the caps.

By the way, I have a Supertester TST and I don't have the manual and chart (other than the built in one) for this model. Anyone have a chart?

Cheers,

Steve

EL3N was replaced by EL33 according to Philips data.

Marc

Hi Guys,

Do you think I can replace El3N (EL33) with a KT61?

Steve

While the pin connections are the same, bias and load figures are different, so not recommended for a permanent fix. Probably OK for a short time to test, but if you are going to make it permanent, make sure you adjust the bias to suit.
Harold

Hi Steve

Check out Kevin Chant's website (http://www.kevinchant.com/). He has all the information for the supertester under the test equipment section, Make sure you get the TST version not TST2 or TVT as the charts don't line up. I am preparing a master listing but am still a few weeks off publishing the details.

A word of warning on these testers, I have one of them and they are Known for giving misleading readings without the changing the Caps in them. They will show shorts that may not be shorts!

Dan
VK5DF

Thanks Harold, maybe I'll just stick to getting the EL33. They are just much more expensive!!

Thanks Dan for the reference. The numbers now make more sense. I'll re run the tests on the valves I have checked. Any advice on the caps would be good. Should I pull it apart and change the caps?

Steve

I would not get a new tube until such time as you have proven it faulty.

There is no place in a test instrument for leaking capacitors. Some resistors may also have wandered but be careful only exact values per circuit can be used, or you may throw it out of any semblance of calibration it had.

No instrument of age is safe from these issues.

I recently found a RC Bridge with oil filled caps, they got tossed as they are as bad as wax paper & I tested a couple to prove it.

I have had the caps in my AVO 7X toss in the towel, others be warned. One was common to the 400VDC range, which went to unbelievable when the cap went.

There is an old 200H Peak meter that turned up here, OP range cap in it had failed. Lastly, but no the end of the happenings, I had a VCT valve tester come in for a mod for the Mains, to make it less dangerous. I noted two wax papers in it which got tossed: leaking like sieves.

Marc

OK, thanks Marc. I'll open it up and have a look. The paper look up chart is a bit dodgy so I'll fix that as well if I can. Thank formal the advice.

Steve

In Radio Days, Australian Bakelite Radios by Peter Sheridan & Ritchie Singer on page 152 there are three Scharnberg Strauss 41's. The next facing page (153) is the same radio, but branded Weldon. (Weldon York?)

The closest possible Weldon circuit I could find in the AORSM is for a Weldon 411, Vol. 8., Page 352. This could be the same or similar circuit to one of Gandhn's 41's as the Weldon 411 is back biased.

Getting closer now. Got most of the caps. Cabinet is looking OK. Harold, it has a really weird station indicator, seams to run on the metal chassis. I'll put in a photo tomorrow if I can. It's quite rusty as well.

Steve