Bendix 526A (USA radio) repaired - UK Vintage Radio Repair and Restoration Discussion Forum

stephanie · 22nd Aug 2005, 4:59 pm

I am (slowly) repairing one of these sets for a co-worker.

http://radioatticarchives.com/images...46)_Dennis.jpg

The bakelite case is a complete wrap-around (kind of like that "toaster" by Kolster-Brandes). To access the chassis, you have to flip the set over and un-do four screws; one at each corner. Then you lift the chassis out of the case.

Standard procedures done so far:

1) wax paper capacitors were all replaced

2) replaced defective volume control (worn track)

3) oiled/greased the tuning shaft that had gone stiff

4) wiped the chassis as much as possible of some surface grime.

5) patched up the very brittle speaker cone with pieces of paper from a tea bag and then coated the cone with spray adhesive (Scotch #77)

6) replaced mains flex

And then there was the vexing problem of why the radio sounded off tune and would oscillate when the volume was turned up louder.

Turns out that it was a missing mica insulator sheet in the antenna trimmer on the tuning condenser. Unfortunately I didn't have the same size so I had to make do with a smaller one from a scrapper.

However it managed to do the job and the radio does pick up the local MW stations reasonably well (it's a single-band five-valve series-string radio) and there is no more oscillation.

I have not attempted to fiddle with the alignment any further for fear of making anything worse.

The mains filter is a metal Aerovox brand can that is mounted on top of the chassis. I left it in place and connected -- the radio has no hum.

I'm still debating with myself whether to replace it or leave as is. That can be a fiddly job if I decide to replace it with new separate 'lytics under the chassis -- that section around the filter terminals is a bit crowded down there.

Opinions?

I guess by next week, the owner will FINALLY get his radio back (after he gave it to me about three or four months ago

)

newlite4 · 23rd Aug 2005, 9:57 am

Stephnie, I think that if the original filter capacitor block is showing no signs of stress then I would leave it in circuit. I have a number of pre-war American TRFs that still run quite happily on their original blocks. As long as the wax capacitors are replaced, then I would say that this is OK for now. If the filter block does fail in the future then it can be replaced.
Neil

dcriner · 6th Sep 2005, 7:17 pm

Steph, that set does look like a toaster.

It's a 1946 model. You could touch up the IF xfmrs by ear.

As far as replacing the filter caps, most people would say replace them, but if it's a big pain, then forget it and let somebody else worry about it in the future.

Doug

stephanie · 19th Sep 2005, 3:40 am

Well!

The mains filters were replaced. Used two 47 mfd units, mounted on a tag strip under the chassis to replace a dual section 40/40 mfd @ 150 Volt can.

Now all that's needed is a touchup of the dial pointer, which will get done as soon as I'm back from holiday.

Aerodyne · 27th Sep 2005, 11:44 am

That's an attractive piece of Bakelite you have there, Stephanie. Congrats on doing a fine restoration job. I'm sure the owner will be very pleased with the outcome.

-Tony

stephanie · 3rd Oct 2005, 9:35 pm

Well, the only work I did was to the electronics, to get it playing again.

The plastic cabinet is still shiney and the dial scale is still intact (sometimes the soft plastic splits because of the curve).

To get into the guts underneath the chassis, you have to remove a bottom metal plate. There's an asbestos pad glue to this panel.

On this radio, thankfully, the glue holding the pad to the metal had dried out, so I was able to shake off the asbestos pad inside a plastic garbage bag which promptly got tossed out.

22nd Aug 2005, 4:59 pm	#1
stephanie Retired Dormant Member Join Date: Jul 2005 Location: New Bern, North Carolina, USA Posts: 346	Bendix 526A (USA radio) repaired I am (slowly) repairing one of these sets for a co-worker. http://radioatticarchives.com/images...46)_Dennis.jpg The bakelite case is a complete wrap-around (kind of like that "toaster" by Kolster-Brandes). To access the chassis, you have to flip the set over and un-do four screws; one at each corner. Then you lift the chassis out of the case. Standard procedures done so far: 1) wax paper capacitors were all replaced 2) replaced defective volume control (worn track) 3) oiled/greased the tuning shaft that had gone stiff 4) wiped the chassis as much as possible of some surface grime. 5) patched up the very brittle speaker cone with pieces of paper from a tea bag and then coated the cone with spray adhesive (Scotch #77) 6) replaced mains flex And then there was the vexing problem of why the radio sounded off tune and would oscillate when the volume was turned up louder. Turns out that it was a missing mica insulator sheet in the antenna trimmer on the tuning condenser. Unfortunately I didn't have the same size so I had to make do with a smaller one from a scrapper. However it managed to do the job and the radio does pick up the local MW stations reasonably well (it's a single-band five-valve series-string radio) and there is no more oscillation. I have not attempted to fiddle with the alignment any further for fear of making anything worse. The mains filter is a metal Aerovox brand can that is mounted on top of the chassis. I left it in place and connected -- the radio has no hum. I'm still debating with myself whether to replace it or leave as is. That can be a fiddly job if I decide to replace it with new separate 'lytics under the chassis -- that section around the filter terminals is a bit crowded down there. Opinions? I guess by next week, the owner will FINALLY get his radio back (after he gave it to me about three or four months ago )

23rd Aug 2005, 9:57 am	#2
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	Re: Bendix 526A (USA radio) repaired Stephnie, I think that if the original filter capacitor block is showing no signs of stress then I would leave it in circuit. I have a number of pre-war American TRFs that still run quite happily on their original blocks. As long as the wax capacitors are replaced, then I would say that this is OK for now. If the filter block does fail in the future then it can be replaced. Neil

6th Sep 2005, 7:17 pm	#3
dcriner Retired Dormant Member Join Date: Aug 2005 Location: Chicago area, USA Posts: 9	Re: Bendix 526A (USA radio) repaired Steph, that set does look like a toaster. It's a 1946 model. You could touch up the IF xfmrs by ear. As far as replacing the filter caps, most people would say replace them, but if it's a big pain, then forget it and let somebody else worry about it in the future. Doug

19th Sep 2005, 3:40 am	#4
stephanie Retired Dormant Member Join Date: Jul 2005 Location: New Bern, North Carolina, USA Posts: 346	Re: Bendix 526A (USA radio) repaired Well! The mains filters were replaced. Used two 47 mfd units, mounted on a tag strip under the chassis to replace a dual section 40/40 mfd @ 150 Volt can. Now all that's needed is a touchup of the dial pointer, which will get done as soon as I'm back from holiday.

27th Sep 2005, 11:44 am	#5
Aerodyne Octode Join Date: Jun 2004 Location: Hampton Vale, Peterborough, UK. Posts: 1,698	Re: Bendix 526A (USA radio) repaired That's an attractive piece of Bakelite you have there, Stephanie. Congrats on doing a fine restoration job. I'm sure the owner will be very pleased with the outcome. -Tony

3rd Oct 2005, 9:35 pm	#6
stephanie Retired Dormant Member Join Date: Jul 2005 Location: New Bern, North Carolina, USA Posts: 346	Re: Bendix 526A (USA radio) repaired Well, the only work I did was to the electronics, to get it playing again. The plastic cabinet is still shiney and the dial scale is still intact (sometimes the soft plastic splits because of the curve). To get into the guts underneath the chassis, you have to remove a bottom metal plate. There's an asbestos pad glue to this panel. On this radio, thankfully, the glue holding the pad to the metal had dried out, so I was able to shake off the asbestos pad inside a plastic garbage bag which promptly got tossed out.