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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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16th Jan 2020, 10:00 pm | #21 |
Rest in Peace
Join Date: Mar 2011
Location: Basildon, Essex, UK.
Posts: 4,100
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Re: New Pup KB 362
Its looking great, I bet you cant wait to see if it works now.
As a last resort I have a power supply to power it here, if you want to make the 50 mile trip to Basildon. Mike |
17th Jan 2020, 11:21 am | #22 |
Heptode
Join Date: Sep 2014
Location: St Albans, Hertfordshire, UK.
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Re: New Pup KB 362
That would be great Dave PM sent I understand HT needs 120v and LT 2v but the GB- I'm not sure about Mike t said GB - (Green) this needs 6V at very little current the Positive connection goes to the HT- how do I give it 6v
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17th Jan 2020, 11:33 am | #23 |
Heptode
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Re: New Pup KB 362
Thanks mike yeah would love to see it work my first battery set that probably sounds funny. The power supply sounds a nice Idea for a later date did you make it yourself
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17th Jan 2020, 9:08 pm | #24 |
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Join Date: Mar 2011
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Re: New Pup KB 362
Yes I made the one on Paul Stenning's site.
https://www.vintage-radio.com/projec...y-set-psu.html Mike |
18th Jan 2020, 12:48 pm | #25 |
Heptode
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Re: New Pup KB 362
Hi Mike that is great and doesn't look to hard for a novice like me it even gives a part list the only thing is unless I got it completely wrong it is for a 90v HT where I'm sure I would need 120v on the HT.
Mark |
18th Jan 2020, 3:03 pm | #26 |
Rest in Peace
Join Date: Mar 2011
Location: Basildon, Essex, UK.
Posts: 4,100
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Re: New Pup KB 362
Oh yes I forgot that, but I would think it should work just about with a 90 volt HT.
Mike |
26th Jan 2020, 4:23 pm | #27 |
Heptode
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Re: New Pup KB 362
Update: with the help from another forum member davebms. (Thanks dave for your help) I have connected a wire to HT- to give the GB+ would the original battery have this made up inside so you didn't need it on radio. We applied power but still no sound. Checking the output transformer and think it is dead. Is there a modern one that I can replace it with. It says it is 400ohm primary
Mark |
26th Jan 2020, 10:21 pm | #28 |
Dekatron
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Location: Newcastle upon Tyne, Tyne & Wear, UK.
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Re: New Pup KB 362
Hi Mark, some of the early HT batteries also had a GB section which would have had the link internally.
Note that you should not run the set with GB disconnected, even for a short time as it can damage valves and transformers. Start at a high negative voltage and reduce; removing HT before changing taps and measure HT current if you can Ed |
27th Jan 2020, 1:37 pm | #29 |
Heptode
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Re: New Pup KB 362
Thanks Ed I have been doing that when checking the transformer on speaker it appears to be dead. That feeds the HT+ to valve 3 so I need to replace it but I don't know with what I can replace it with most I have looked at are not 400ohms can you still get one at 400ohms I think getting it rewound would cost more than its worth
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27th Jan 2020, 3:28 pm | #30 |
Heptode
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Re: New Pup KB 362
Photo of what I need to replace HT is 120v
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27th Jan 2020, 3:59 pm | #31 | |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
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Re: New Pup KB 362
Quote:
http://www.r-type.org/pdfs/pm22a.pdf If the transformer is faulty and all else fails then RS components still appear to supply a transformer that should do if space permitts: https://uk.rs-online.com/web/p/audio...rmers/2106475/ Here's the data sheet for that transformer: https://docs.rs-online.com/7d2d/0900766b80473a76.pdf You can see from the data that it will match 15k to 3 ohms. Lawrence. Last edited by ms660; 27th Jan 2020 at 4:05 pm. |
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27th Jan 2020, 6:25 pm | #32 |
Heptode
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Re: New Pup KB 362
Thank you for that Lawrence. Am I right I have to wire it up like this. Also if i only applied 90v to HT would i get some noise from speaker or should i give it the full 120v
Mark |
27th Jan 2020, 6:43 pm | #33 |
Dekatron
Join Date: Apr 2011
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Re: New Pup KB 362
I would connect as per the data sheet and I would operate the receiver with 120 volts HT and the correct LT and grid bias voltage.
Having said that are you sure the original output transformer is faulty? A simple resistance measurement of the primary winding and the secondary winding should confirm. Lawrence. |
27th Jan 2020, 7:57 pm | #34 |
Heptode
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Re: New Pup KB 362
I did a continuity check across the primary and didn't get anything so I'm thinking that that's the fault. Is the connections wrong on my drawing as I'm not sure how to connect the new one that you recommended I'm not that knowledgeable on op's I can have another look at the old OP transformer
Mark Last edited by rockinmark; 27th Jan 2020 at 8:07 pm. |
27th Jan 2020, 8:15 pm | #35 | |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
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Re: New Pup KB 362
Quote:
Primary 1 & 4 (13-15k) Secondary C & D (3-4 ohms) Lawrence. |
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27th Jan 2020, 8:43 pm | #36 |
Pentode
Join Date: May 2017
Location: Ware, Hertfordshire, UK.
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Re: New Pup KB 362
Hello all Mark was at my house to use
My battery’s the 90 volt was just how My battery’s were set at LT and grid bias we’re correct. With the primary disconnected There was no continuity on the primary possibly it may be worth removing the transformer to look if the broken wire Can be re soldered ? Dave |
27th Jan 2020, 8:53 pm | #37 |
Heptode
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Re: New Pup KB 362
Thank Lawrence and dave. I will take it out and see if I can see any wire broken
Mark |
28th Jan 2020, 4:47 pm | #38 |
Heptode
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Re: New Pup KB 362
I have taken the transformer off and couldn't see any brakes. From there I thought I have nothing to lose removed it from speaker and took it apart to see if I could see anything so the only way to find the brake would be to start unwinding it at this point I think easier to get a new one
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29th Jan 2020, 3:30 pm | #39 |
Heptode
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Re: New Pup KB 362
I have just received the new transformer that Lawrence suggested the interesting thing is it fits inside the old one when I take out the old winding part. Got to clean it up but it will look a bit more original
Mark |
9th Mar 2020, 10:58 pm | #40 |
Heptode
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Re: New Pup KB 362
Update I have now finished this pup trf radio been very interesting first of all I would like to thank everyone for their input in helping me finish this set thanks to dave, davebms for showing and teaching me a bit about it. And thank to ed dinning and jerry cathoderay57 for supplying the valves. Without everybody's help I wouldn't have finished it
Mark Last edited by rockinmark; 9th Mar 2020 at 11:04 pm. |