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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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13th Jul 2017, 8:35 pm | #1 |
Hexode
Join Date: Oct 2006
Location: Edenderry, Republic of Ireland.
Posts: 428
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Philco 48-2810
Hi,The mains dropper has gone open circuit on the Philco 48-2810, I want to know if a dropper from a Dac90a will fit. Thanks Dick.
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13th Jul 2017, 8:58 pm | #2 |
Dekatron
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 3,762
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Re: Philco 48-2810
Now let's try again my last post was removed for some bizarre reason !
do you have a circuit with all the valves listed . |
13th Jul 2017, 10:44 pm | #3 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Philco 48-2810
14S7 7B7 14B6 50A5 35Y4
It's a 150mA heater chain so it's unlikely that a 100mA chain DAC90A dropper would be any use- it would be overloaded 100% even if the resistances were correct! The circuit shows a 320R resistor upstream of the rectifier heater and a 290R one between the rectifier and output valve heaters. 10W rated W/W resistors should be OK, 330R and 300R would probably suit for 240 rather than 230V operation.
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13th Jul 2017, 10:56 pm | #4 |
Hexode
Join Date: Oct 2006
Location: Edenderry, Republic of Ireland.
Posts: 428
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Re: Philco 48-2810
I do not have a circuit diagram. Please let me know where I can get one. Thank you Dick.
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14th Jul 2017, 12:32 pm | #5 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
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Re: Philco 48-2810
No posts have been deleted or edited.
The circuit is available from Radiomuseum: http://www.radiomuseum.org/r/philco_48_2810.html, but also may be anglicised as the B2810, which is on Paul's DVD. |
15th Jul 2017, 9:18 am | #6 |
Dekatron
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 3,762
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Re: Philco 48-2810
Thanks for clearing that up Bill, don't know what happened to it then. Mick.
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23rd Jul 2017, 8:08 pm | #7 |
Hexode
Join Date: Oct 2006
Location: Edenderry, Republic of Ireland.
Posts: 428
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Re: Philco 48-2810
Hello again,I have the B-2810 circuitry but it is not the valve line up of the 48-2810. I cannot download the radio museum just yet. Should I wait until I get the circuit for it?
Regards, Dick. |
23rd Jul 2017, 8:42 pm | #8 |
Moderator
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Location: Exeter, Devon and Poole, Dorset UK.
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Re: Philco 48-2810
Hi Dick
Are you saying you have reached your Radiomuseum daily or 30 day limit as a non-member for downloads? If it the resistor in the filament chain its 290 Ohm it will need to be 20W its dropping 115V There is also a power resistor in the rectifier circuit do you know which one is faulty? Cheers Mike T
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23rd Jul 2017, 10:25 pm | #9 |
Hexode
Join Date: Oct 2006
Location: Edenderry, Republic of Ireland.
Posts: 428
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Re: Philco 48-2810
I am a member at the radio museum but I have mislaid my password so I must wait until my son comes to help me out. Dick
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23rd Jul 2017, 10:31 pm | #10 |
Moderator
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Re: Philco 48-2810
Hi Dick pleased to hear your a member.
If you have an 115 V transformer and you set the radio to run on 115V both resistors are out of circuit so you could asses the rest of the set whilst you wait for your password to be sorted. If it going to take a while to sort your password drop me a PM. Cheers Mike T
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24th Jul 2017, 12:12 pm | #11 | |
Dekatron
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Location: Leominster, Herefordshire, UK.
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Re: Philco 48-2810
Quote:
You can still download limited amounts of info as a guest. It's a bit of a rigmarole, but just the circuit shouldn't take too long.
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24th Jul 2017, 4:20 pm | #12 | |
Heptode
Join Date: Mar 2017
Location: Cedar Grove, Wisconsin, USA.
Posts: 823
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Re: Philco 48-2810
Quote:
The set uses the same circuit as the U.S. sets but uses a 7S7 instead. All the Philco's sold here use the 7A8 FC valve. |
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24th Jul 2017, 10:07 pm | #13 |
Hexode
Join Date: Oct 2006
Location: Edenderry, Republic of Ireland.
Posts: 428
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Re: Philco 48-2810
Hi, would it be too much to ask for someone to send me a diagram incorporating the mains dropper as for show but with an appropriate capacitor/resistor dropper showing values and place in the circuit.It would be very much appreciated. Regards Dick.
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25th Jul 2017, 5:03 pm | #14 | |
Heptode
Join Date: Mar 2017
Location: Cedar Grove, Wisconsin, USA.
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Re: Philco 48-2810
Quote:
I calculate a 2.2 mfd A.C. type capacitor for the voltage drop. Sorry, I can't provide a schematic of the way the cap should be connected. |
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26th Jul 2017, 9:59 pm | #15 |
Hexode
Join Date: Oct 2006
Location: Edenderry, Republic of Ireland.
Posts: 428
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Re: Philco 48-2810
Hi again, I have taken a look at the valve lineup in the Philco, I have Four numbers as follows 14S7. 12Q7. 35L6 and 35 Y4. The other valve has the number missing. The dial bulb is quoted at 35 volts. Would this lineup work. Regards Dick
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26th Jul 2017, 10:41 pm | #16 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Philco 48-2810
The lineup is plausible, though odd, with that mix of Loctal and Octal valves.
The missing one could be a 12K7 or 12SK7 (top cap or single ended) if Octal, or something else again if Loctal. The total heater volts is 108V plus panel lamp? This is a different lineup from the RM circuit which has the 14S7 7B7 14B6 50A5 35Y4 lineup I quoted earlier. That uses the odd US arrangement with the panel lamp wrapped round the rectifier filament tap and adds up to about 117V. Snip of heater chain circuit attached.
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....__________ ....|____||__|__\_____ .=.| _---\__|__|_---_|. .........O..Chris....O |
27th Jul 2017, 8:07 am | #17 |
Dekatron
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Location: W.Butterwick, near Doncaster UK.
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Re: Philco 48-2810
I was not aware you could download anything as a non member of Radio Museum?
Sorry,I have drifted with others a bit.
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27th Jul 2017, 8:21 am | #18 |
Moderator
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Re: Philco 48-2810
Hi HB
Non members can download up to 3 pages a day or 10 per month. It's a bit of a faf much better to be a member Dick is a member just having login trouble. Cheers Mike T
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
27th Jul 2017, 8:33 am | #19 | |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
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Re: Philco 48-2810
Quote:
The 290R resistor is in the heater chain, but it only carries the heater current (150mA), it doesn't drop 115V. So about 6.25W. The 300R resistor in the rectifier circuit is also part of the heater dropper chain- that one carries both the heater current and the half wave HT pulses so it dissipates rather more.
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27th Jul 2017, 8:57 am | #20 |
Moderator
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Re: Philco 48-2810
I blame sleep deprevation
Cheers Mike T
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