Perdio Radio Model PR99 Grosvenor - UK Vintage Radio Repair and Restoration Discussion Forum

Celestial · 17th Jan 2021, 4:45 pm

Received as not working. Changed the AF115 as it was completely faulty. Fitted a replacement AF115 obtained from a supplier as a good example with very low leakage. All old electrolytics changed in both modules as most were way beyond their marked value or open circuit.

Has anyone on the forum serviced this particular set? The two transistors in the IF module are 2G416B types. I do not have any reference to these in my data books.
I have reassembled the set and there are absolutely no signals on any waveband.

I wondered if the IF transistors do need changing in a similar way to the ones in the Roberts R500 radios. If so can any one advise me what types I should use please please.
Many thanks.

Herald1360 · 18th Jan 2021, 12:34 am

2G416B is likely similar to 2G416 with some selected characteristics.

2G416: https://alltransistors.com/transisto...transistor=213 looks like a pnp Ge vhf transistor vaguely similar to the AF11x series but higher Ft. It's in a TO18 can so similar in size to AF12x series.

No idea whether they're affected by tin whiskers.

Are you certain you NOS AF115 is good? They grow whiskers regardless of use or not and a good one yesterday could be duff today.

Celestial · 18th Jan 2021, 4:21 pm

Hi Chris,
Thanks for your reply. The reason that I used what is I believe a "good" example of the AF115 tarnsistor is that the leads are very much longer than the replacement AF125. On the PCB of this radio the holes for the tarnsistor leads are very widely spaced. I know that these old AF11x series can be unreliable.
I use an Atlas DAC55 tester to check to see if they are any good.
I could use an AF200 which is very similar characteristics to the AF115 or somehow or other try and get an AF125 or AF124 to fit the widely spaced holes.
Thanks also for the information about the 2G416B Transistors.

Herald1360 · 18th Jan 2021, 7:20 pm

Some careful leg extension (use old AF11x legs?) of AF12x lead outs combined with a bit of small bore sleeving can solve the spacing and leg crossing problems of the substitution.

PTFE or silicone rubber sleeving is ideal but PVC will do- just be quick and decisive with the soldering.

Celestial · 19th Jan 2021, 4:31 pm

Hi,
Thank you very much indeed for the update.
I will have another look at this radio when I get a chance.
Thanks to everyone for your replies.

majoconz · 23rd Jan 2021, 11:29 pm

I have one of those too - from our local auction site as a bit of nostalgia as I bought one new in the mid-60s from a shop in Croydon. Although mine works it's prone to oscillation even though I have replaced all the electrolytics - I suspect the IF module but it's a pig to get to the other side of the PC board. PP9 batteries are unavailable here so I found a copy of the cardboard case and fitted a 6xAA cell holder inside - works well and sort of looks the part if you're not too picky!

17th Jan 2021, 4:45 pm	#1
Celestial Triode Join Date: Nov 2018 Location: Swindon, Wiltshire, UK. Posts: 43	Perdio Radio Model PR99 Grosvenor Received as not working. Changed the AF115 as it was completely faulty. Fitted a replacement AF115 obtained from a supplier as a good example with very low leakage. All old electrolytics changed in both modules as most were way beyond their marked value or open circuit. Has anyone on the forum serviced this particular set? The two transistors in the IF module are 2G416B types. I do not have any reference to these in my data books. I have reassembled the set and there are absolutely no signals on any waveband. I wondered if the IF transistors do need changing in a similar way to the ones in the Roberts R500 radios. If so can any one advise me what types I should use please please. Many thanks.

18th Jan 2021, 12:34 am	#2
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Perdio Radio Model PR99 Grosvenor 2G416B is likely similar to 2G416 with some selected characteristics. 2G416: https://alltransistors.com/transisto...transistor=213 looks like a pnp Ge vhf transistor vaguely similar to the AF11x series but higher Ft. It's in a TO18 can so similar in size to AF12x series. No idea whether they're affected by tin whiskers. Are you certain you NOS AF115 is good? They grow whiskers regardless of use or not and a good one yesterday could be duff today. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

18th Jan 2021, 4:21 pm	#3
Celestial Triode Join Date: Nov 2018 Location: Swindon, Wiltshire, UK. Posts: 43	Re: Perdio Radio Model PR99 Grosvenor Hi Chris, Thanks for your reply. The reason that I used what is I believe a "good" example of the AF115 tarnsistor is that the leads are very much longer than the replacement AF125. On the PCB of this radio the holes for the tarnsistor leads are very widely spaced. I know that these old AF11x series can be unreliable. I use an Atlas DAC55 tester to check to see if they are any good. I could use an AF200 which is very similar characteristics to the AF115 or somehow or other try and get an AF125 or AF124 to fit the widely spaced holes. Thanks also for the information about the 2G416B Transistors.

18th Jan 2021, 7:20 pm	#4
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Perdio Radio Model PR99 Grosvenor Some careful leg extension (use old AF11x legs?) of AF12x lead outs combined with a bit of small bore sleeving can solve the spacing and leg crossing problems of the substitution. PTFE or silicone rubber sleeving is ideal but PVC will do- just be quick and decisive with the soldering. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

19th Jan 2021, 4:31 pm	#5
Celestial Triode Join Date: Nov 2018 Location: Swindon, Wiltshire, UK. Posts: 43	Re: Perdio Radio Model PR99 Grosvenor Hi, Thank you very much indeed for the update. I will have another look at this radio when I get a chance. Thanks to everyone for your replies.

23rd Jan 2021, 11:29 pm	#6
majoconz Heptode Join Date: Jan 2008 Location: Ashhurst, Manawatu, New Zealand Posts: 571	Re: Perdio Radio Model PR99 Grosvenor I have one of those too - from our local auction site as a bit of nostalgia as I bought one new in the mid-60s from a shop in Croydon. Although mine works it's prone to oscillation even though I have replaced all the electrolytics - I suspect the IF module but it's a pig to get to the other side of the PC board. PP9 batteries are unavailable here so I found a copy of the cardboard case and fitted a 6xAA cell holder inside - works well and sort of looks the part if you're not too picky! Attached Thumbnails __________________ Cheers - Martin ZL2MC