Granada Television Brochure, 1970s
Long Gone UK TV Shops
Memories of a Derwent Field Service Engineer
PYE Australia Circa 1971
Radios-TV VRAT
Fabulous Fablon
Thorn TX10 Chassis
Crusty-TV Museum, Analogue TV Network
Philips N1500 Warning!
Rumbelows
Thorn EMI Advertising
Thorn’s Guide to Servicing a VCR
Ferguson 3V24 De-Robed
Want to tell us a story?
Video Circuits V15 – Tripler Tester
Thorn Chassis Guide
Remove Teletext Lines & VCR Problems
Ceefax (Teletext)
Suggestions
Website Refresh
Colour TV Brochures
1970s Lounge Recreation
CrustyTV Vintage Television Museum
Linda Lovelace Experience
Humbars on a Sony KV2702
1972 Ultra 6713
D|E|R Service “The Best”
The one that got away
Technical information
The Line Output Stage
The map
Tales of a newly qualified young engineer.
Tales of a Radio Rentals Van Boy
Sanyo SMD
Disastrous Company Rebranding
1969 Philips G22K511
Memories Of The TV Trade
Crazy house
Dirty TV screens
Dual Standard and Single Standard CTV’s
Radios-TV on YouTube
The Winter of 62/63
A domestic audio installation
1979 Ferguson Videostar Deluxe 3V16
Music centre modifications
Unusual record player modification
B&K 467 Adapters
Mishaps In The Trade
1971 Beovision 3200
1971 Bush CTV1120
Granada Television Brochure, 1970s
Long Gone UK TV Shops
Memories of a Derwent Field Service Engineer
PYE Australia Circa 1971
Radios-TV VRAT
Fabulous Fablon
Thorn TX10 Chassis
Crusty-TV Museum, Analogue TV Network
Philips N1500 Warning!
Rumbelows
Thorn EMI Advertising
Thorn’s Guide to Servicing a VCR
Ferguson 3V24 De-Robed
Want to tell us a story?
Video Circuits V15 – Tripler Tester
Thorn Chassis Guide
Remove Teletext Lines & VCR Problems
Ceefax (Teletext)
Suggestions
Website Refresh
Colour TV Brochures
1970s Lounge Recreation
CrustyTV Vintage Television Museum
Linda Lovelace Experience
Humbars on a Sony KV2702
1972 Ultra 6713
D|E|R Service “The Best”
The one that got away
Technical information
The Line Output Stage
The map
Tales of a newly qualified young engineer.
Tales of a Radio Rentals Van Boy
Sanyo SMD
Disastrous Company Rebranding
1969 Philips G22K511
Memories Of The TV Trade
Crazy house
Dirty TV screens
Dual Standard and Single Standard CTV’s
Radios-TV on YouTube
The Winter of 62/63
A domestic audio installation
1979 Ferguson Videostar Deluxe 3V16
Music centre modifications
Unusual record player modification
B&K 467 Adapters
Mishaps In The Trade
1971 Beovision 3200
1971 Bush CTV1120
HMV1117 output valve
A colleague has asked me to take a look at his great aunt's HMV 1117, which he found in his loft the other day.
When I took the back off the first thing I noticed was a 6V6GT in place of the KT61. Is this an acceptable substitute?
Thanks.
Gus.
Hi Gus, the radio museum guys say that it is an ok replacement,
But the cathode resistor should be changed from 90 ohms to 270 ohms (1 watt)
Read the full storey here.
http://www.radiomuseum.org/tubes/tube_kt61.html
Thanks Rabbitstew, that link saved me from making a mistake (I thought KT61 and EL33 were the same).
That 6V6GT has to go and I hope I have a KT61 in my stash.
Gus.
That 6V6GT has to go
Gus.
But only into the valve stash! It's one of the all-time popular small output valves, with economical heater for its size (at least for indirect heater). And it'll only gain in value,
Colin.
Hi Gus
In case you were not aware of it, this site is also good for looking up valve data and equivelents.
http://www.r-type.org/search.php
and this site is good for looking up transistor data and equivalents.
http://alltransistors.com/
If you get stuck I think I have a KT61 or an EL33
Mike
I think some of Duncans Amps schematics have been hijacked. If you go to schematics - Marshall and click on most of the amps schematics then you get some Spanish looking site. Does anybody know Duncan to tell him.
Mike
I think some of Duncans Amps schematics have been hijacked. If you go to schematics - Marshall and click on most of the amps schematics then you get some Spanish looking site. Does anybody know Duncan to tell him.
Mike
it is a 404 (URL not present) message in Italian but what is possibly expected there maybe can be found below - its not anything sinister other than these "free hosting" companies moving stuff around, and the Italian chap who was sharing the schematics has had all the links on his website changed due to this. OK not quite related to the radio output valve but it might be worth keeping track of the new link as it could be useful to somebody...
http://www.pierluigipollano.ilbello.com/Schematics.html
Thanks for all the links. I've seen most of them before, but not the one Michael sent, cheers Michael.
As for the 6V6, it won't get thrown away; I collect them as spares for my Fender amps.
Thanks for the offer Mike. I think I'm okay for a KT61, but if I'm not, you will be the first to know.
After a quick look at the 1117, there's not much visibly wrong: some sticky push buttons and a broken dial drive. If I'm lucky, the wire part will be intact and I will only have to replace the cord. I hate fixing dial cords.
Gus.
I removed the chassis tonight and discovered that the cathode resistor is wire-wound and 100 ohms. I wonder if the set was operated much with the 6V6/100 ohms combo and what would be the outcome if it was?
On the good news front, the tuning drive wire is intact, with one end connected to the drum. The cord part of the drive is missing. The underside of the chassis looks original and all of the wiring is in good condition.
The only potential bad news is that my KT61 has a loose base and rattles copiously, so my next job is to test all of the valves. I believe some of them may be hard to get.
Gus.
The 6V6 would wear out quickly, the output transformer might burn out (or winding insulation damaged so it fails later), a valve or metal rectifier would be badly worn and the mains transformer could even burn out (or winding insulation damaged so it fails later).
it's the same effect as having a slightly (but not very) leaky grid audio coupling capacitor.
The output valve will be replaced with a 25L6 which I found in my stash and which was very good when tested. The 100-ohm resistor has been replaced by a 180-ohm 2-watt resistor.
The tuning drive has been re-strung, a four-hour job the other night (and it's a fairly simple one too).
I have started cleaning the cabinet, which lived for some time in a smoky environment. My main aim is to preserve the perfect HMV transfer, so I have a question. Will all-purpose cleaning foam damage the transfer? I'm not going to touch the grille cloth because it is intact but grubby. I don't want it to be clean but torn.
As for replacing the waxies, that looks like it will be easy because of the sensible and spacious layout underneath the chassis.
Gus.
Be careful with the transfer.
I have just cleaned the dial on a TR82 and I spotted a slight trace of the red dial colour on the cleaning cloth. It was enough for me to use caution. I was prepared to work fast if it needed to be dried fast. It did
The output valve will be replaced with a 25L6 which I found in my stash and which was very good when tested. The 100-ohm resistor has been replaced by a 180-ohm 2-watt resistor.
Gus.
Hi Gus did I miss something the 25L6 has a 26V filament.
Cheers
Mike T
I don't care if it was a bargain whats it doing on my kitchen table. www.cossor.co.uk
It depends on the letter(s) after the type number what the heater voltage is.
We need to see the full part number.
http://en.wikipedia.org/wiki/25L6
I agree with Jeffrey
In this series the first numbers indicate the approximate filament voltage and this is pretty consistent in American numbered Octal valves.
The 50L6 has a 48V 0.16 V filament and the 6L6 is 6.3V 0.9A
Cheers
Mike T
I don't care if it was a bargain whats it doing on my kitchen table. www.cossor.co.uk
The 25L6 if clearly for an AC/DC set and another heater transformer would be needed for it to be used in an AC set.
Sorry, I meant 6P25.
Gus.
That makes a lot more sense
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