Sonora 50s metal portable

[maxhifi]

That speaker looks a little suspiciously Japanese and non original - TV is very neat though, I like it a lot

[David Roper]

Is that a 12DQ6 and is that what's called for? My 8" Emerson had a 6DQ6 when I got it, but it had been subbed in for the original correct 6BQ6.

[bandersen]

Originally Posted by maxhifi

That speaker looks a little suspiciously Japanese and non original - TV is very neat though, I like it a lot

Yes, it does have JAPAN stamped on it. Can't tell if it's original or not though.

Originally Posted by David Roper

Is that a 12DQ6 and is that what's called for? My 8" Emerson had a 6DQ6 when I got it, but it had been subbed in for the original correct 6BQ6.

It's a 17DQ6 and it is what's called for. Here's the whole lineup

4BC5
6CL8
6AN8
6U8
8AW8
8AW8
4DT6
8CM7
17DQ6
17AX4
1X2
10ADP4

Plus a couple 1N60 for video detector and horizontal AFC

[dieseljeep]

Originally Posted by David Roper

Is that a 12DQ6 and is that what's called for? My 8" Emerson had a 6DQ6 when I got it, but it had been subbed in for the original correct 6BQ6.

My preference would be a 6DQ6, but both of the transformer powered, eight inch sets, the RCA and Emerson were originally equipped with a 6BQ6.

[David Roper]

A 6AV5 could have done it without breakin' a sweat; 6DQ6 seems like extreme overkill.

[bandersen]

I think it's fair to say the engineering on this set is a little shaky in general. For example they used a 47 ohm 10 watt dropper resistor in the 0.45 amp filament string. That comes out to 9.5 watts so they really should have used at least a 13 watt resistor or, better yet, a 15. Also, assuming 117 VAC, a 51 ohm dropper would be a better choice.

Anyway, I just finished ohming out all the transforms, choke, yoke, flyback etc. and they're all dead on so the restoration is a go

[dieseljeep]

Originally Posted by David Roper

A 6AV5 could have done it without breakin' a sweat; 6DQ6 seems like extreme overkill.

The GE 9" sets use a 18A5, which is a simular design tube with a 300ma heater, operating on low B+. Also the GE has a 70 degree CRT, where the set in question is a 90 degree CRT and a voltage doubler power supply.

[bandersen]

I removed the speaker so I could replace the caps underneath.




I don't recall seeing an Astron Corp cap before.

[Eric H]

Astron sounds like a sub-division of Spacely Sprockets.

[Reece]

Isn't or wasn't Golden Voice (as on that speaker) the way that Motorola branded their speakers? Of course, anything is possible across the years and across the oceans.

[dieseljeep]

Originally Posted by Reece

Isn't or wasn't Golden Voice (as on that speaker) the way that Motorola branded their speakers? Of course, anything is possible across the years and across the oceans.

The speaker was probably removed from a scapped Motorola product. They were one of the first U.S. firms to use Japanese parts.
Regarding the Astron capacitor, many East coast firms, like Olympic used their products.

[bandersen]

I pried off the HV cage and found the coating flaking off the flyback. I'll spread some HV silicone on it.


The power supply was very easy to recap. The new parts are much smaller and there is a convenient terminal strip with unused terminals for the diodes. I left out any series droppers for now. If the B+ ends up being to high, I'll increase the value of the fusistor.

[dieseljeep]

I was looking over your fine workmanship. It's amazing how small the new issue electrolytic and film caps are.
The Astron cap was a dual section, wasn't it? Also I see, there's another large paper electrolytic below.

[bandersen]

The Astron was a single section 200uF @ 150 VDC. That plus a 140uF @ 300VDC, a couple diodes and a choke form the voltage doubler B+ supply. The other cap peeking out below is a three section electrolytic.

[dieseljeep]

Originally Posted by bandersen

The Astron was a single section 200uF @ 150 VDC. That plus a 140uF @ 300VDC, a couple diodes and a choke form the voltage doubler B+ supply. The other cap peeking out below is a three section electrolytic.

I worked on a few 17" Sonoras, Sonora built airlines and a lot of Trav'lers.
Never a 10 inch, but I noticed, how similar the circuit is. The big bomber on the left of your original picture is the 140mfd @ 300 wvdc. What brand was that cap.? I see you reversed the location.