Hacker RP18 Sovereign - UK Vintage Radio Repair and Restoration Discussion Forum

SteveCG · 29th Aug 2017, 1:22 pm

The VHF section of this Hacker no-longer works. Long Wave and Medium Wave are fine.

Being of the age where the VHF/FM IF unit used the dreaded AF114 Transistors I assumed that it was one of them that had 'tin-whiskered' - however this, I think, is not the case.

The radio uses a German made tuner "G*****" the rest of the name is illegible. I have tried looking for the LO leakage signal - nothing. I've even tried looking for the 10.7 Mc/s IF output whilst tuning across the band - nothing there either. So I suspect I have a failed LO transistor.

My question is this: Are these tuners generally reliable?

BTW the supply voltage to the tuner was about 7.5 volts

G6Tanuki · 29th Aug 2017, 1:27 pm

Gorler? They made a lot of FM-tuner-modules in the 60s and 70s.

ms660 · 29th Aug 2017, 1:30 pm

Gorler from all accounts.

According to this they use AF121, AF125 types:

http://www.radiomuseum.org/r/hacker_..._rp18rp_1.html

Lawrence.

paulsherwin · 29th Aug 2017, 2:06 pm

The AF12x series are not known to be unreliable, but failure is still possible of course.

SteveCG · 30th Aug 2017, 11:16 am

Folks, indeed it is a Gorler.

A couple of voltages - as measured with a DMM.

For the main battery voltage of 16.9 V, I have +7.56 V on pin 6 of the tuner module wrt the chassis. This pin has the red colour code HT wire connected to it and also a 0.1 uF polyester capacitor connected to pin 4 which in turn is linked to the chassis.

SteveCG · 31st Aug 2017, 2:46 pm

Some more tuner voltage readings. Can anybody tell me if they are approximately what they should be?

Gorler tuner module pin-outs; voltages measured with a DMM wrt the chassis:

1 chassis
2 Green lead, 0V
3 Orange lead, +6.11V
4 chassis
5 Blue lead, 0V
6 Red lead, +7.4V
7 Green lead, (I/F output)

I've included the lead insulation colour - just in case Hacker had a 'house style'
Also the voltages are slightly different to those before because the PSU is unregulated and the mains voltage was 5 Volts lower the second time.

29th Aug 2017, 1:22 pm	#1
SteveCG Nonode Join Date: Jun 2009 Location: Herefordshire, UK. Posts: 2,495	Hacker RP18 Sovereign The VHF section of this Hacker no-longer works. Long Wave and Medium Wave are fine. Being of the age where the VHF/FM IF unit used the dreaded AF114 Transistors I assumed that it was one of them that had 'tin-whiskered' - however this, I think, is not the case. The radio uses a German made tuner "G*****" the rest of the name is illegible. I have tried looking for the LO leakage signal - nothing. I've even tried looking for the 10.7 Mc/s IF output whilst tuning across the band - nothing there either. So I suspect I have a failed LO transistor. My question is this: Are these tuners generally reliable? BTW the supply voltage to the tuner was about 7.5 volts

29th Aug 2017, 1:27 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: Hacker RP18 Sovereign Gorler? They made a lot of FM-tuner-modules in the 60s and 70s.

29th Aug 2017, 1:30 pm	#3
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Hacker RP18 Sovereign Gorler from all accounts. According to this they use AF121, AF125 types: http://www.radiomuseum.org/r/hacker_..._rp18rp_1.html Lawrence.

29th Aug 2017, 2:06 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Hacker RP18 Sovereign The AF12x series are not known to be unreliable, but failure is still possible of course.

30th Aug 2017, 11:16 am	#5
SteveCG Nonode Join Date: Jun 2009 Location: Herefordshire, UK. Posts: 2,495	Re: Hacker RP18 Sovereign Folks, indeed it is a Gorler. A couple of voltages - as measured with a DMM. For the main battery voltage of 16.9 V, I have +7.56 V on pin 6 of the tuner module wrt the chassis. This pin has the red colour code HT wire connected to it and also a 0.1 uF polyester capacitor connected to pin 4 which in turn is linked to the chassis.

31st Aug 2017, 2:46 pm	#6
SteveCG Nonode Join Date: Jun 2009 Location: Herefordshire, UK. Posts: 2,495	Re: Hacker RP18 Sovereign Some more tuner voltage readings. Can anybody tell me if they are approximately what they should be? Gorler tuner module pin-outs; voltages measured with a DMM wrt the chassis: 1 chassis 2 Green lead, 0V 3 Orange lead, +6.11V 4 chassis 5 Blue lead, 0V 6 Red lead, +7.4V 7 Green lead, (I/F output) I've included the lead insulation colour - just in case Hacker had a 'house style' Also the voltages are slightly different to those before because the PSU is unregulated and the mains voltage was 5 Volts lower the second time.