Can anyone identify this rectifier? - UK Vintage Radio Repair and Restoration Discussion Forum

ViragoRider · 16th Sep 2023, 4:46 pm

This rectifier is in a radio I'm currently working on. The schematic calls for a 5Z4. The only markings I can find are on the bottom and have no reference in Valve museum.

I believe someone has fitted it as a replacement at some point and I don't want to power the radio up even on a dim bulb unless I know it is a viable alternative to the 5Z4.

The base was very loose when I got it and had been sellotaped to the glass. Needless to say, the Sellotape had perished and was baked on to the glass. I've removed as much as I can and super glue came to the rescue. Thank you for your insights.

Maarten · 16th Sep 2023, 5:23 pm

The codes confirm Mullard. 1227 is the factory type code, which is not in the list or in my own files yet, but I guess it could be a GZ30 (5Z4).

ms660 · 16th Sep 2023, 5:44 pm

http://www.r-type.org/exhib/aaa1829.htm

?

Lawrence.

Leon Crampin · 16th Sep 2023, 5:47 pm

5U4G. Directly heated with the correct missing pins for this type. Note that it's directly heated and has a 3A filament current, so not a correct replacement for a 5Z4.

Leon.

Maarten · 16th Sep 2023, 6:35 pm

The GZ30 has exactly the same missing pins, so identification this way is probably not possible. Measuring the heater current would be useful, though I think a few more valves have this pinout and some may have the same heater current.

ms660 · 16th Sep 2023, 6:41 pm

The base reminds me of Cossor, GEC, Marconi.

Lawrence.

60 oldjohn · 16th Sep 2023, 8:09 pm

Quote:

Originally Posted by ViragoRider

I've removed as much as I can and super glue came to the rescue. .

Let us know the outcome, Super Glue is not recommended for thin heated glass, different expansion rates usually cracks the glass in time. Cheap 2 part Epoxy would be a better fix.

John.

Leon Crampin · 16th Sep 2023, 9:49 pm

The rectifier image in the first post is of a directly heated type in a large "G" size envelope. This must rule out the GZ30/5Z4 which is indirectly heated. The 5U4 matches the image.

Leon.

16th Sep 2023, 4:46 pm	#1
ViragoRider Tetrode Join Date: Apr 2022 Location: Nottingham, Nottinghamshire, UK. Posts: 63	Can anyone identify this rectifier? This rectifier is in a radio I'm currently working on. The schematic calls for a 5Z4. The only markings I can find are on the bottom and have no reference in Valve museum. I believe someone has fitted it as a replacement at some point and I don't want to power the radio up even on a dim bulb unless I know it is a viable alternative to the 5Z4. The base was very loose when I got it and had been sellotaped to the glass. Needless to say, the Sellotape had perished and was baked on to the glass. I've removed as much as I can and super glue came to the rescue. Thank you for your insights. Attached Thumbnails

16th Sep 2023, 5:23 pm	#2
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,062	Re: Can anyone identify this rectifier? The codes confirm Mullard. 1227 is the factory type code, which is not in the list or in my own files yet, but I guess it could be a GZ30 (5Z4).

16th Sep 2023, 5:44 pm	#3
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,452	Re: Can anyone identify this rectifier? http://www.r-type.org/exhib/aaa1829.htm ? Lawrence.

16th Sep 2023, 5:47 pm	#4
Leon Crampin Octode Join Date: Nov 2005 Location: Surrey, UK. Posts: 1,845	Re: Can anyone identify this rectifier? 5U4G. Directly heated with the correct missing pins for this type. Note that it's directly heated and has a 3A filament current, so not a correct replacement for a 5Z4. Leon.

16th Sep 2023, 6:35 pm	#5
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,062	Re: Can anyone identify this rectifier? The GZ30 has exactly the same missing pins, so identification this way is probably not possible. Measuring the heater current would be useful, though I think a few more valves have this pinout and some may have the same heater current.

16th Sep 2023, 6:41 pm	#6
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,452	Re: Can anyone identify this rectifier? The base reminds me of Cossor, GEC, Marconi. Lawrence.

16th Sep 2023, 9:49 pm	#8
Leon Crampin Octode Join Date: Nov 2005 Location: Surrey, UK. Posts: 1,845	Re: Can anyone identify this rectifier? The rectifier image in the first post is of a directly heated type in a large "G" size envelope. This must rule out the GZ30/5Z4 which is indirectly heated. The 5U4 matches the image. Leon.