Record player valve query - UK Vintage Radio Repair and Restoration Discussion Forum

K.C.pye1958 · 30th Apr 2017, 10:07 pm

Hello,
I have a portogram autogram and have two valves a UL84 and UY85 to install, can someone tell me which goes which on the circuit board
Please see photos

all help will be much appreciated

Nuvistor · 30th Apr 2017, 10:19 pm

I cannot tell which socket from those photos but the UL84 will be connect to the volume control, perhaps through a capacitor.

A clear photo of underneath the circuit board may help.
Frank

Tractorfan · 30th Apr 2017, 10:31 pm

Hi,
The UY85 is the rectifier and the UL84 is the output pentode. The volume control is connected to pin 2 of one of the valve sockets (as seen from the underside of the PCB, and pin 7 goes to the output transformer, so that is the one for the UL84.
Cheers, Pete.

K.C.pye1958 · 30th Apr 2017, 10:36 pm

hello here are other photos

K.C.pye1958 · 30th Apr 2017, 10:40 pm

Hello,
looking at the photo would the UY 85 be on the left and the UL84 on the right?

frankmcvey · 30th Apr 2017, 11:08 pm

I would guess so, but you really need to either look under the PCB or to use a multimeter to establish continuity between the valve base pins and other components. For example, the volume control wiper connects directly to the control grid of the UL84. (Pin 2 of the UL84 would connect to the centre tag on the volume control). Make sure it's switched off and unplugged before doing this check.

A simple look underneath should show that one valve has 4 wires going to it and the other has 6 wires going to it. The 4 wire valve base will be the UY85.

However, it might be that the manufacturer has used a couple of the normally unused pins on the valve base(s) as simple wiring tags so save money, which would complicate things.

Cheers,

Frank

Oldcodger · 30th Apr 2017, 11:57 pm

Lettering on the valve gives
U= HEATER VOLTS.
Y= RECTIFIER.
L = amplifier valve, possibly ( from memory a pentode) .
Simply trace wiring, and where output of transformer goes- that is where UL goes. Other valve ,goes ,by process of elimination in other socket.
QED.

julie_m · 1st May 2017, 12:20 am

You really need to see the back of the board, then it will be obvious which valve goes where. The UL84 connects to the volume and tone controls, and the loudspeaker transformer. The UY85 connects to the power switch and the big silver can capacitor.

What was the problem with the original valves? It's unusual for them both to require replacement .....

peter_sol · 1st May 2017, 9:00 am

I suspect you are not very technical.
The UY85 is likely to go next to the the silver can capacitor.

Edward Huggins · 1st May 2017, 10:52 am

Were these two valves in that same postion when you bought it, as per your photo? The 100% certainty is the 4 wires only to the valve holder underside are for the UY85.

30th Apr 2017, 10:07 pm	#1
K.C.pye1958 Pentode Join Date: May 2015 Location: Cork, Munster, Ireland Posts: 114	Record player valve query Hello, I have a portogram autogram and have two valves a UL84 and UY85 to install, can someone tell me which goes which on the circuit board Please see photos all help will be much appreciated Attached Thumbnails

30th Apr 2017, 10:19 pm	#2
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Valve query I cannot tell which socket from those photos but the UL84 will be connect to the volume control, perhaps through a capacitor. A clear photo of underneath the circuit board may help. Frank

30th Apr 2017, 10:31 pm	#3
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Re: Valve query Hi, The UY85 is the rectifier and the UL84 is the output pentode. The volume control is connected to pin 2 of one of the valve sockets (as seen from the underside of the PCB, and pin 7 goes to the output transformer, so that is the one for the UL84. Cheers, Pete. __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

30th Apr 2017, 10:36 pm	#4
K.C.pye1958 Pentode Join Date: May 2015 Location: Cork, Munster, Ireland Posts: 114	Re: Valve query hello here are other photos Attached Thumbnails

30th Apr 2017, 10:40 pm	#5
K.C.pye1958 Pentode Join Date: May 2015 Location: Cork, Munster, Ireland Posts: 114	Re: Valve query Hello, looking at the photo would the UY 85 be on the left and the UL84 on the right?

30th Apr 2017, 11:08 pm	#6
frankmcvey Rest in Peace Join Date: Jan 2015 Location: Cottesmore, East Midlands, UK. Posts: 858	Re: Valve query I would guess so, but you really need to either look under the PCB or to use a multimeter to establish continuity between the valve base pins and other components. For example, the volume control wiper connects directly to the control grid of the UL84. (Pin 2 of the UL84 would connect to the centre tag on the volume control). Make sure it's switched off and unplugged before doing this check. A simple look underneath should show that one valve has 4 wires going to it and the other has 6 wires going to it. The 4 wire valve base will be the UY85. However, it might be that the manufacturer has used a couple of the normally unused pins on the valve base(s) as simple wiring tags so save money, which would complicate things. Cheers, Frank Last edited by frankmcvey; 30th Apr 2017 at 11:15 pm.

30th Apr 2017, 11:57 pm	#7
Oldcodger Nonode Join Date: Oct 2014 Location: West Midlands, UK. Posts: 2,181	Re: Valve query Lettering on the valve gives U= HEATER VOLTS. Y= RECTIFIER. L = amplifier valve, possibly ( from memory a pentode) . Simply trace wiring, and where output of transformer goes- that is where UL goes. Other valve ,goes ,by process of elimination in other socket. QED.

1st May 2017, 12:20 am	#8
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Valve query You really need to see the back of the board, then it will be obvious which valve goes where. The UL84 connects to the volume and tone controls, and the loudspeaker transformer. The UY85 connects to the power switch and the big silver can capacitor. What was the problem with the original valves? It's unusual for them both to require replacement ..... __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

1st May 2017, 9:00 am	#9
peter_sol Octode Join Date: Aug 2003 Location: Welwyn Garden City, Herts. UK. Posts: 1,906	Re: Record player valve query I suspect you are not very technical. The UY85 is likely to go next to the the silver can capacitor.

1st May 2017, 10:52 am	#10
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,327	Re: Record player valve query Were these two valves in that same postion when you bought it, as per your photo? The 100% certainty is the 4 wires only to the valve holder underside are for the UY85. __________________ Edward.