Hacker Super Sovereign RP75 woes - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

mhennessy · 17th Sep 2010, 12:41 am

The sleeving is put on by the set manufacturer, and the colours will be their preference - nothing to do with the actual transistor. The red or blue dot on the case signifies collector, base is in the middle, emitter on the other side. If the sleeving on the Hacker wasn't wrecked, I'd suggest transferring it to the new transistors...

Interesting that you've now got a "T3". Still no idea what T2 and T3 are - maybe transistors that have a low VCE because of some process failure, but sold for this purpose where they'll never see more than a volt or two? Does your T3 have a red or blue dot?

Ian E G7OLT · 17th Sep 2010, 9:45 am

Also, is a T3 NPN or PNP?. Darren would either need to measure it or find a schematic for the Philips tape recorder he found at the dump.

mhennessy · 17th Sep 2010, 10:20 am

Hi Ian,

That's why I asked about the colour of the collector dot. Assuming it's still there, it ought to be a reliable indicator...

Would love to know more about these transistors - I suspect that someone will have an obscure Mullard publication from the 1970s that explains all - but I'm sure an AC128 or similar would be absolutely fine in this position.

17th Sep 2010, 12:41 am	#21
mhennessy Dekatron Join Date: Jul 2007 Location: Evesham, Worcestershire, UK. Posts: 4,244	Re: Hacker Super Sovereign RP75 woes The sleeving is put on by the set manufacturer, and the colours will be their preference - nothing to do with the actual transistor. The red or blue dot on the case signifies collector, base is in the middle, emitter on the other side. If the sleeving on the Hacker wasn't wrecked, I'd suggest transferring it to the new transistors... Interesting that you've now got a "T3". Still no idea what T2 and T3 are - maybe transistors that have a low VCE because of some process failure, but sold for this purpose where they'll never see more than a volt or two? Does your T3 have a red or blue dot?

17th Sep 2010, 9:45 am	#22
Ian E G7OLT Pentode Join Date: May 2009 Location: Byfield, Northamptonshire UK. Posts: 112	Re: Hacker Super Sovereign RP75 woes Also, is a T3 NPN or PNP?. Darren would either need to measure it or find a schematic for the Philips tape recorder he found at the dump.

17th Sep 2010, 10:20 am	#23
mhennessy Dekatron Join Date: Jul 2007 Location: Evesham, Worcestershire, UK. Posts: 4,244	Re: Hacker Super Sovereign RP75 woes Hi Ian, That's why I asked about the colour of the collector dot. Assuming it's still there, it ought to be a reliable indicator... Would love to know more about these transistors - I suspect that someone will have an obscure Mullard publication from the 1970s that explains all - but I'm sure an AC128 or similar would be absolutely fine in this position.