Checking midget output transformer - UK Vintage Radio Repair and Restoration Discussion Forum

SurreyNick · 29th May 2014, 7:45 pm

Hi
This is the midget output transformer from my battery operated receiver (HT 120v / LT 2v accumulator). The writing on the side reads:

PRI:
BLUE & RED
MAINS PEN
& BATT. TRIODE
BLUE & GREEN
BATT. PEN
MAX 30 M/A. D.C.

Being a novice, that's pretty-much double Dutch to me.

Is there a simple way to check it's working properly without reconnecting it to the receiver?

Thanks

Nick

Station X · 29th May 2014, 8:11 pm

The best you'll be able to do is use a meter on ohms range to check the continuity of the windings. If they show open circuit, then the transformer is toast. If they show continuity, then the transformer is probably OK, but it may have short circuited turns.

SurreyNick · 29th May 2014, 8:19 pm

OK Graham, thanks, I think I know how to do that.
Regards
Nick

Herald1360 · 30th May 2014, 12:07 am

Quote:

Originally Posted by SurreyNick

Hi
This is the midget output transformer from my battery operated receiver (HT 120v / LT 2v accumulator). The writing on the side reads:

PRI:
BLUE & RED
MAINS PEN-------- Taps for typical mains powered radio output pentode for about 5K load
& BATT. TRIODE- Taps for typical battery radio output triode for about 5K load
BLUE & GREEN
BATT. PEN--------- Taps for typical battery radio output pentode for about 10K load
MAX 30 M/A. D.C.- Maximum continuous primary DC (anode current of O/P valve)

HTH

SurreyNick · 30th May 2014, 12:14 am

Thanks Chris, it does help

Regards
Nick

29th May 2014, 7:45 pm	#1
SurreyNick Heptode Join Date: Apr 2014 Location: Wigton, Cumbria, UK. Posts: 728	Checking midget output transformer Hi This is the midget output transformer from my battery operated receiver (HT 120v / LT 2v accumulator). The writing on the side reads: PRI: BLUE & RED MAINS PEN & BATT. TRIODE BLUE & GREEN BATT. PEN MAX 30 M/A. D.C. Being a novice, that's pretty-much double Dutch to me. Is there a simple way to check it's working properly without reconnecting it to the receiver? Thanks Nick Attached Thumbnails

29th May 2014, 8:11 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Checking midget output transformer The best you'll be able to do is use a meter on ohms range to check the continuity of the windings. If they show open circuit, then the transformer is toast. If they show continuity, then the transformer is probably OK, but it may have short circuited turns. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

29th May 2014, 8:19 pm	#3
SurreyNick Heptode Join Date: Apr 2014 Location: Wigton, Cumbria, UK. Posts: 728	Re: Checking midget output transformer OK Graham, thanks, I think I know how to do that. Regards Nick

30th May 2014, 12:14 am	#5
SurreyNick Heptode Join Date: Apr 2014 Location: Wigton, Cumbria, UK. Posts: 728	Re: Checking midget output transformer Thanks Chris, it does help Regards Nick