Late 1920s Eveready Model 1 TRF Set need info

[vortalexfan]

Originally Posted by Kevin Kuehn

Take a look at American Bosch model 28. I'm pretty sure Bosch made those for Eveready. http://www.nostalgiaair.org/Resources/767/M0040767.htm

Yep, took a look at that and it sure was the same unit, the Eveready version of the service information was missing quite a bit of helpful information including the parts listing and the information about the transformer and the "filter can" assembly and how to service them, and the rest of the resistors and capacitors and their values.

So as far as the Filter Can assembly goes, since it was meant to be removed and replaced as a whole assembly I'm assuming that in order to replace the old filter capacitors I would need to just cut out the old filter caps and just solder new capacitors onto where the old capacitors that were in the filter can soldered to?

Also I'm going to assume the original Filter Choke is more than likely fine yet so it should be fine to leave that in circuit am I correct?

As for the old filter capacitors go, I'm assuming I should just go with 450V Caps to be on the safe side since they didn't specify a voltage in the service information?

Also I see the 3 Meg Grid Leak Resistor in the parts list, but I don't see the second fuse looking resistor that was on top of the chassis listed in the parts list, unless I'm missing something...

Thanks for your help.

Edit: I figured out what that second fuse style resistor is on the top of the radio chassis, its the 50,000 Ohm (50k Ohm) Plate Resistor which measures open and I searched eBay and couldn't find anything.
I know of someone who might have the part (its an older gentleman who goes by Glasslinger on YouTube, who works on these old 1920s vintage TRF sets all the time) but I'm not sure how to go about contacting him and or if he would even be willing to send me one of his resistors if he had one.

[Kevin Kuehn]

How about leave the defective 50k above chassis for originality, snip the wiring below and add a modern replacement under chassis? It's no more sacrilegious than changing caps. The filter choke, who knows, you'll find out if it's good once you trace the wiring or fire the set up under load. These things are so old that the copper wire used had impurities along with not so good insulating varnish which allows the wire to oxidize and corrode open over time. Same issues with the stage coupling transformers. The finer wire winding's are most subject to corroding open.

[vortalexfan]

Originally Posted by Kevin Kuehn

How about leave the defective 50k above chassis for originality, snip the wiring below and add a modern replacement under chassis? It's no more sacrilegious than changing caps. The filter choke, who knows, you'll find out if it's good once you trace the wiring or fire the set up under load. These things are so old that the copper wire used had impurities along with not so good insulating varnish which allows the wire to oxidize and corrode open over time. Same issues with the stage coupling transformers. The finer wire winding's are most subject to corroding open.

Ok, thanks! I might just do that. What wattage should I use for that plate resistor? They didn't specify a wattage in the service manual.

Also if the filter choke is bad, could I just replace that with a resistor?

Thanks.

[Kevin Kuehn]

Originally Posted by vortalexfan

Ok, thanks! I might just do that. What wattage should I use for that plate resistor? They didn't specify a wattage in the service manual.

Also if the filter choke is bad, could I just replace that with a resistor?

Thanks.

Half watt should be more than enough. You could use a resistor but you won't get as much filtering with the stock value capacitors.

Here's an interesting post from over on ARF.

https://antiqueradios.com/forums/vie...hp?f=6&t=72312

Towards the end is an explanation of how to neutralize the set(as in Neutradyne). Good to know since the manufacture didn't include it in the Riders service literature. Actually they probably did include that process in a more complete service manual available to their dealers.

[vortalexfan]

OK, so I was testing my voltages and my power resistors under the power supply of the radio and apparently my 1.5k Ohm 10W WW Resistor just died on me somehow instead of measuring 1.5k Ohms on the multimeter it measured 14 Ohms which is weird because the 5k Ohm "B" Resistor and the 300 Ohm Bias Resistors test fine the 1.5k Ohm Bias resistor is measuring only 14 Ohms, any ideas as to why that would be?

Which I think that might be why I'm not getting any filiment glow or anything out of the Output tubes because the 1.5k Ohm Bias Resistor is part of the output tube filiment wiring.

Thanks for your help.

EDIT: I removed the 1500 Ohm Bias Resistor from the circuit and retested it and it tested fine, apparently I was just reading the resistance wire windings between the two terminal strips where the filiment wires attached to across the bias resistor to ground rather than the bias resistor's actual value.

I think what actually is wrong is that the output tubes are just bad and I think they failed because the output tubes weren't replaced as a matched pair when one of the tubes failed at one point in time (which apparently according to my Rider's Tube Substitution Guidebook with the 71A tube when you go to replace the tubes when they are in a push-pull configuration they need to be replaced as a matched set or they could fail prematurely due to biasing issues between the two tubes, which I think is precisely what happened in my case).

[Electronic M]

Originally Posted by Kevin Kuehn

How about leave the defective 50k above chassis for originality, snip the wiring below and add a modern replacement under chassis? It's no more sacrilegious than changing caps. The filter choke, who knows, you'll find out if it's good once you trace the wiring or fire the set up under load. These things are so old that the copper wire used had impurities along with not so good insulating varnish which allows the wire to oxidize and corrode open over time. Same issues with the stage coupling transformers. The finer wire winding's are most subject to corroding open.

Some of those plug in fuse like grid bias resistors I've seen gutted and the ends attached to a hollow tube with a modern resistor inside. Either approach is valid and which to choose depends on how much of a stickler for originality you are and/or how much time and effort you want to spend.

[vortalexfan]

Originally Posted by Electronic M

Some of those plug in fuse like grid bias resistors I've seen gutted and the ends attached to a hollow tube with a modern resistor inside. Either approach is valid and which to choose depends on how much of a stickler for originality you are and/or how much time and effort you want to spend.

I have no idea how I would go about gutting this fuse style resistor without breaking it.

Also I did take a look over at Playthings of the Past's Website and they seem to have what I'm looking for resistor wise (the glass fuse style resistors) but I didn't see any in the 50,000 Ohm rating so I shot the owner a message to see if he could look through his glass resistor stash to see if he had any that were rated for 50,000 Ohms. I'm waiting to hear back from him yet (I sent him a message at 10 o'clock this morning and it is the weekend so I may not hear back until next week sometime).

[Kevin Kuehn]

Originally Posted by vortalexfan

I have no idea how I would go about gutting this fuse style resistor without breaking it.

Also I did take a look over at Playthings of the Past's Website and they seem to have what I'm looking for resistor wise (the glass fuse style resistors) but I didn't see any in the 50,000 Ohm rating so I shot the owner a message to see if he could look through his glass resistor stash to see if he had any that were rated for 50,000 Ohms. I'm waiting to hear back from him yet (I sent him a message at 10 o'clock this morning and it is the weekend so I may not hear back until next week sometime).

Just a heads up. The owner of PTOP passed away a while back and apparently someone bought the entire inventory, but he's not saying who he is at this point or when he'll be able to reopen the business. I'd be very surprised if you hear anything back via the old email.

https://antiqueradios.com/forums/vie...things+of+past

https://antiqueradios.com/forums/vie...things+of+past

[vortalexfan]

Originally Posted by Kevin Kuehn

Just a heads up. The owner of PTOP passed away a while back and apparently someone bought the entire inventory, but he's not saying who he is at this point or when he'll be able to reopen the business. I'd be very surprised if you hear anything back via the old email.

https://antiqueradios.com/forums/vie...things+of+past

https://antiqueradios.com/forums/vie...things+of+past

Ok, I didn't know, I just saw a reference to the website in a few posts over at the Philco Phorum, but I didn't pay much attention to how old the threads were that the posts were in.

I'll just have to keep a look out on ebay I guess.

[vortalexfan]

Originally Posted by Kevin Kuehn

Just a heads up. The owner of PTOP passed away a while back and apparently someone bought the entire inventory, but he's not saying who he is at this point or when he'll be able to reopen the business. I'd be very surprised if you hear anything back via the old email.

https://antiqueradios.com/forums/vie...things+of+past

https://antiqueradios.com/forums/vie...things+of+past

OK, so I found some regular resistors in my stash that I think might work in my radio as a replacement for the bad fuse style resistor.

I found a box of 47k Ohm 1W 2% tolerance Flameproof resistors that are branded RCA, a package with a 56K Ohm 1W 2% Flameproof Resistor that is Branded Sylvania and I have a package of 56k Ohm 1/2W Carbon Film Resistors that I had left over from when I was restoring my Meck TV last year that either one of those I think should work in this unit.

I think I could just solder it under the chassis between the two points where the resistor holder above ties into the circuit and then just leave the old fuse style resistor in the holder above the chassis for appearances sake (I cleaned up the glass housing of the old resistor and I looked inside and it looked like there wasn't anything in there anymore which might explain why it measured open).

Does any of these resistors I mentioned stick out as far as one that might work better than the other in this position?

Also I found a couple of capacitors in my capacitor stash that might work in place of the old filter caps in the filter supply circuit, one is a 4.7 MFD 250 WVDC Electrolytic and the other is a 2.2 MFD 100 WVDC Electrolytic.

Would those work fine in the filter cap positions on this radio seeing as they didn't specify a Working Voltage for the original filter caps?

Also the 5,000 Ohm "B" Resistor in this radio's Power Supply/Audio Circuit measures open as well, and I was wondering what kind of wattage of resistor it is, its rather large and looks like it might be a 5 or 10 Watt WW Power Resistor but I'm not sure as it doesn't have any information written on it.

Thanks for your help.

[Kevin Kuehn]

Originally Posted by vortalexfan

I found a box of 47k Ohm 1W 2% tolerance Flameproof resistors that are branded RCA, a package with a 56K Ohm 1W 2% Flameproof Resistor that is Branded Sylvania and I have a package of 56k Ohm 1/2W Carbon Film Resistors that I had left over from when I was restoring my Meck TV last year that either one of those I think should work in this unit.

I think I could just solder it under the chassis between the two points where the resistor holder above ties into the circuit and then just leave the old fuse style resistor in the holder above the chassis for appearances sake (I cleaned up the glass housing of the old resistor and I looked inside and it looked like there wasn't anything in there anymore which might explain why it measured open).

Does any of these resistors I mentioned stick out as far as one that might work better than the other in this position?

Really any of them should be fine. According to the voltage/current chart that resistor will be dropping around 45v, so 45v x 2ma is a whopping 90mw of dissipation.

Originally Posted by vortalexfan

Also I found a couple of capacitors in my capacitor stash that might work in place of the old filter caps in the filter supply circuit, one is a 4.7 MFD 250 WVDC Electrolytic and the other is a 2.2 MFD 100 WVDC Electrolytic.

Would those work fine in the filter cap positions on this radio seeing as they didn't specify a Working Voltage for the original filter caps?

Assuming B+ at the second filter around 175v, I would use 4.7 mfd @ 250wvdc for 102 and 103. That'll give you some good headroom and a little extra filtering. For that matter you could use a couple 10mfd.

Originally Posted by vortalexfan

Also the 5,000 Ohm "B" Resistor in this radio's Power Supply/Audio Circuit measures open as well, and I was wondering what kind of wattage of resistor it is, its rather large and looks like it might be a 5 or 10 Watt WW Power Resistor but I'm not sure as it doesn't have any information written on it.

175v - 90v = 85v across the 5k.
85v/5000 = 17ma.
85v x 17ma = 1.45watts. So a 5 watt should be very conservative.

Everything is ballpark based on the values listed in the Bosch model 28 voltage/current chart and schematic.