Zenith 10-H-571 "Spinet" - Printable Version
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+--- Thread: Zenith 10-H-571 "Spinet" (/showthread.php?tid=16039)
RE: Zenith 10-H-571 "Spinet" - morzh - 03-12-2017
I got lucky, most resistors stayed even though I bought all the values. Desoldering those would be a huge plus to the already RPITA.
Aligned the BC and IF. In fact it was pretty much in alignment. I checked the SW bands and decided they didn't need alignment.
Anyways, sprayed the band switch and the tone ctl switch with Deoxit.
Still on the fence about the volume control. It's pretty involved and if ruined.....good luck finding one. It has more than one tap.
Stringing needs to be tightened. And probably some bearings and bushings lubed.
It'll be at least another couple of weeks before it goes back into the cabinet, now that I only have weekends to work on it.
RE: Zenith 10-H-571 "Spinet" - Arran - 03-13-2017
Mike;
I noticed something that is rather unusual about the audio output stage in this radio, it has a resistor, a choke, and a capacitor across the primary of the audio output transformer, and on top of that it also has a cap between the plate of the audio output tube and ground. This, combined with the used of what looks like a Rola made loudspeaker, likely accounts for the nice sounding audio. It's curious to me that they would manufacture a 10 tube set, with an FM band, that has a single ended audio output stage though. This was probably why they felt compelled to add the extra tone correction components, in an attempt to eliminate some of the distortion that comes with a single ended stage. Brand Z was a strange company in this way, but at least this model used a proper rectifier tube.
Regards
Arran
RE: Zenith 10-H-571 "Spinet" - morzh - 03-13-2017
Arran
but at least this model used a proper rectifier tube.
....which I had to change
- the only bad tube in the whole radio. The rest, except the 6V6, are all loctals and I had to scrape every single pin of every single tube - all tested bad first due to oxidized pins.As for Class A distortion - many audiophiles prefer Class A for small systems. Class A has a bit more of non-linearity but then has no crossover. Pick one
The filter you refer to, interestingly enough, is also present in the radio with the same model number and the letter "R" at the end and it is connected via a switch there that is only engaged when in FM mode.
Which tells me it could be used at higher frequencies. Since it is a series resonant filter and will at the resonant frequency become a 100 Ohm resistor (the frequency is unknown as I have no inductor's data) I think it might be used to compensate the fact that the impedance of the speaker-transformer system rises with frequency and with FM giving us 15kHz could exceed the optimal value somewhat upsetting the power transfer, so they tried to lower it somewhat by paralleling a 100 Ohm resistor at higher frequencies.
RE: Zenith 10-H-571 "Spinet" - Eliot Ness - 03-14-2017
Great job Mike
. All of that re-stuffing paid off, it looks beautiful with all of the original capacitors in there!
RE: Zenith 10-H-571 "Spinet" - morzh - 03-14-2017
Thanks John, thanks everyone.
Tonight I used my "time off" to open and clean the volume control and the power switch. The switch was working but was a bit dirty.
Volume had lapses and scratching.
I opened it, no small doing, the resistor has 6 lugs, and the face plate on one side had the tabs soldered to it. The resistor itself is cylindrical, not flat, and very, very narrow.
As usual, Deoxit spay, then a little dab of Deoxit/Lithium grease. Now it is quiet and seems to have no lapses.
Question: who knows what belt should there be to drive the pulley that drives the tunng cap from the knurled cylinder attached to the flywheel? I have a rope with ends tied together as a large nod. It is loose. I wonder if it s original or should there be a belt?
KCMike, could you possibly look in yours?
RE: Zenith 10-H-571 "Spinet" - KCMike - 03-14-2017
I looked and since the chassis is still in the radio I can't see the belt your asking about. There is a small dial string type going around the tuning cap pulley. I found this site but I don't know anything about the company and there is no picture of what your ordering. I do have a bunch of JFD belts but they are the flat type.
If it uses that type I can check and see if I have one for you. By the way mine does not turn the tuning cap so its probably broke also.
http://www.adamsradio.com/page9.html
Edit Here is the home page shows round belts
http://www.adamsradio.com/page1.html
RE: Zenith 10-H-571 "Spinet" - morzh - 03-14-2017
Mike
Yes I do know Adams radio, I ordered belts from him for my other Zenith console some 5 years ago.
He has it, thanks.
I will get it, but for my education I'd like to know what kind of belt is there. In my old Z it was a leather belt flat but Adams sells only neoprene ones and that's what I had to get..
Mike
RE: Zenith 10-H-571 "Spinet" - Eliot Ness - 03-14-2017
The link KCMike posted for dial belts (Adams) is a good one, that's where most people buy their Zenith belts.
Another method is to buy dial belt material from Mark Oppat, cut to size and super glue it together... believe-it-or-not, if you use fresh glue, it works really well:
http://radios.hfhosting.net/product/dial-belt/
Edit: the original belts were a flat woven material. I have some NOS JFD replacement belts but I quit using them because they are so old and dry they were slipping.
RE: Zenith 10-H-571 "Spinet" - KCMike - 03-14-2017
Well this might work also. It's a flat or they call it square belt.
http://www.radiodaze.com/dial-belt-kit-6-foot/
RE: Zenith 10-H-571 "Spinet" - Eliot Ness - 03-14-2017
(03-14-2017, 08:46 PM)KCMike Wrote: Well this might work also. It's a flat or they call it square belt.
http://www.radiodaze.com/dial-belt-kit-6-foot/
Yes, that works well also. The flat (square) belt is what Alan Jesperson sells and I've used it successfully, but on a motor drive Zenith I'd probably go ahead and order belts from Adams.
RE: Zenith 10-H-571 "Spinet" - morzh - 03-14-2017
I bought Adams' belt.
Don't want to be gluing and cutting.
In a way it'd be simpler as to put a loop over the gear I have to disassemble it first while the rope can be cut and glued in place. But then I feel the gear might use some lube anyway.
RE: Zenith 10-H-571 "Spinet" - KCMike - 03-14-2017
I was thinking the same thing but wanted to just throw out that option. I see an order from Adams for mine in the future.
RE: Zenith 10-H-571 "Spinet" - OldRestorer - 03-15-2017
I am so not happy about putting a new belt in my Strat...
Ok, Maybe not a strat but a Zenith....
So much work but I dont trust the "glue yourself" belts.
I got mine from Adam too...
RE: Zenith 10-H-571 "Spinet" - morzh - 03-15-2017
Actually putting the belt in the 9-S-262 Z was a snap....well, almost a snap. Plus the whole mechanism was seized so it needed a blast of Lithium grease anyway. And by seized I do mean frozen solid. Unlike this one that is rotating fine but methinks after 76 years might as well lube it.
I forgot the second occasion I bought Adams' belts, but I ordered twice before. They worked exactly as supposed to both times. I just hope this IS the belt 'cause there is the second string but it is a, well, string and not a belt so I am sure I bought the correct one.
RE: Zenith 10-H-571 "Spinet" - Eliot Ness - 03-15-2017
(03-15-2017, 08:04 AM)OldRestorer Wrote: ......So much work but I dont trust the "glue yourself" belts.....
I was leery of them too but if you use fresh super glue and cut at an angle they work quite well. Just glue an O-Ring together sometime and test how strong it is.
But as I mentioned, on a motor drive Zenith, I would use Adams belts. I used to buy O-Rings from a local place here in town but they didn't last long at all, they would crack and eventually break. I think the Adams belts must be much better because I haven't heard anyone complain about them.