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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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4th Sep 2017, 2:58 pm | #21 | |
Hexode
Join Date: Aug 2014
Location: Dartford, Kent, UK.
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Re: Info Needed for Little Maestro 10 AC/DC
Quote:
I am sure that the repair or alteration made in the past was made with the best intentions but I would feel much happier knowing the way it was meant to be. |
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4th Sep 2017, 4:39 pm | #22 |
Hexode
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Re: Info Needed for Little Maestro 10 AC/DC
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4th Sep 2017, 4:46 pm | #23 |
Dekatron
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Re: Info Needed for Little Maestro 10 AC/DC
No problem, what's going to happen with the valve base skirts?
Lawrence. |
4th Sep 2017, 6:08 pm | #24 |
Hexode
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Re: Info Needed for Little Maestro 10 AC/DC
Hello Lawrence,
I am trying not to touch them until I get the HT sorted out and then see if they work. It really is a shame that getting replacements is so expensive now! Is it possible to glue/cement then in place? That would be my choice if it is. The one thing I am learning is that Trader Service Sheets are a bit like the Oracle - unreliable! I have the AC version of this set waiting in the wings, sheet 912, and there are so many differences from the sheet in the L1 - L4 and S1 - S6 area that I have had to draw it out to make sense - and it doesn't!!! Cheers John |
4th Sep 2017, 6:30 pm | #25 |
Dekatron
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Re: Info Needed for Little Maestro 10 AC/DC
Some Trader sheets do have errors, but sometimes they have more useful information in them than the manufactures manual such as various modification revisions etc.
Manufactures manuals tended to be shoved out around product release time then amendment/error sheets shoved out later after all the snagging, the results of the snagging period in many cases was based on the service techs moans/groans/findings when they were out in the field or on the bench, many of those mod sheets etc have not survived. Many original manufactures manuals contain errors, I speak from my experience in the servicing trade. Lawrence. |
5th Sep 2017, 12:02 am | #26 |
Hexode
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Re: Info Needed for Little Maestro 10 AC/DC
I was just looking over other sheets for the Little Maestro and found that the diagram for the De Lux, service sheet 871, is a closer match to my set than the information in sheet 913!
So, was this due to manufacturing or the actions of a repair engineer who decided what was better a long time ago? Any ideas? Cheers John Last edited by AC/HL; 5th Sep 2017 at 2:48 pm. Reason: Rule B8 |
5th Sep 2017, 2:55 am | #27 | |
Heptode
Join Date: Mar 2017
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Re: Info Needed for Little Maestro 10 AC/DC
Quote:
All I did is lined up the crimps with the bakelite base and wrapped wire tightly around the base and soldered it together, where the crack is. |
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5th Sep 2017, 8:25 am | #28 | |
Dekatron
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Re: Info Needed for Little Maestro 10 AC/DC
Quote:
The Deluxe model I would say is the forerunner of the 10 series models but note that it's heater dropper resistor is a Line Chord type, not a chassis mounted resistor.... Which ever way you cut it you have to remember that many manufactures did all sorts of changes to many models...without notification, which sometimes left the service techs scratching their heads when comparing what was in front of them to what the manual was telling them....Sometimes troubleshooting isn't painting by numbers Lawrence. |
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5th Sep 2017, 8:28 am | #29 | |
Dekatron
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Re: Info Needed for Little Maestro 10 AC/DC
Quote:
Lawrence. |
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5th Sep 2017, 8:32 am | #30 | |
Hexode
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Location: Dartford, Kent, UK.
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Re: Info Needed for Little Maestro 10 AC/DC
Quote:
I also wondered if there was a modern glue/cement that could be used in conjunction with your suggestion to improve the seating of the valve? |
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5th Sep 2017, 9:34 am | #31 |
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Re: Info Needed for Little Maestro 10 AC/DC
I've had sets with completely different chassis fitted from new. I suppose that old chassis were used up on later model upgrades and newer chassis fitted to older models to clear cabinet stocks.
There were lots of variations of the Little Maestro anyway. |
5th Sep 2017, 11:48 am | #32 |
Hexode
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Re: Info Needed for Little Maestro 10 AC/DC
That makes sense. I keep forgetting how old these sets are and how manufacturing operated back then.
I am, still, convinced that this chassis is 'almost' the same as sheet 913 as all of the values follow this sheet and the replacement R16 has been setup for around 830 ohms. R14 is so badly discoloured that it is hard to tell what it was originally. So wiring it back up with the correct resistor is my priority - something to keep me quiet for a while! Thanks for your help John |
5th Sep 2017, 4:46 pm | #33 |
Heptode
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Re: Info Needed for Little Maestro 10 AC/DC
I generally will use a small bead of silicone sealant before reseating the skirt, wrap it tightly with the wire, but wait to solder it, until the sealant sets up.
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5th Sep 2017, 5:12 pm | #34 | |
Heptode
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Re: Info Needed for Little Maestro 10 AC/DC
Quote:
The lowest priced ones used pin-drive magnetic speakers, that didn't need an output transformer. Those sets had that "tinny" sound. |
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5th Sep 2017, 6:39 pm | #35 |
Hexode
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Re: Info Needed for Little Maestro 10 AC/DC
No hint of asbestos in the line cord - so I don't think that is a dropper. But the diagram of the deluxe shows the limiting resistor connect at the source of AC - but presumably the whole cord is resistive so how can that be?
Arghh! |
5th Sep 2017, 7:00 pm | #36 |
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Re: Info Needed for Little Maestro 10 AC/DC
Some line cords had an extra wire in the bundle to carry full mains to the set as well as neutral and the inline flexible dropper for the heater chain. Useful on early US sets where the heaters didn't even add up to 110V and for UK sets where the higher HT was useful for the output stage at least.
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5th Sep 2017, 7:12 pm | #37 |
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Re: Info Needed for Little Maestro 10 AC/DC
Used to have great fun when people had tried to put a 13A plug on one of these 3 core line cords! Funny, they never got them to work!
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7th Sep 2017, 5:19 pm | #38 | |
Heptode
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Re: Info Needed for Little Maestro 10 AC/DC
Quote:
People tried to replace the plug themselves and would miss the tiny resistance wire. |
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7th Sep 2017, 10:04 pm | #39 | |
Dekatron
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Re: Info Needed for Little Maestro 10 AC/DC
Quote:
First shows general layout underneath. Second shows the 100 ohm limiter resistor connected to the anode of the 35Z4GT. Third shows the 1.5K smoothing resistor and the 10K common screen feed resistor. Forth shows the 100 ohm pilot lamp shunt. Fifth shows the top chassis layout....the dropper is in a different place.
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8th Sep 2017, 12:36 am | #40 |
Hexode
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Re: Info Needed for Little Maestro 10 AC/DC
That's what I needed - a big thank you.
So . . . . the anode goes to the mains via a 100 ohm resistor. And the mains joint on the 100 ohm resistor is then connected onto the dropper resistor. And just for a sanity check are you using, I suppose you must be, a 35Z4GT rectifier? My 'layout' conforms to that in service sheet 913. I do NOT have a heat shield on my dropper which explains why the back cover is burnt and crumbly and broken. Your chassis is a LOT cleaner than mine! So after all of these discussions it looks like, in my opinion, that Service Sheet 913 is wrong or not the correct revision for this set. AND there are a LOT of different versions of this model. My new 35Z4GT should arrive on Monday and I am replacing wax caps and cleaning up the mess and then I can find out what else needs doing. Once again thank you. John |