PYE PF85 - schematic - info - UK Vintage Radio Repair and Restoration Discussion Forum

jimscoper · 18th Jul 2021, 9:56 am

Picked up a PF85 plus car kit and lapel mike at boot fair - without battery. Applied 9 volts and it behaves like a radio and puts out about 137MHz and draws about 170mA on PTT.

Now wondering what to do with it. Basically looks like a conventional NBFM radio. To do much with it would need to alter the LO and disable the squelch. Made a bit more difficult by the mysterious OM601, 603, 602 and 605 modules.

Are schematics available? And what was the 'proper' battery voltage and how long the 'rubber duck'?

BTW, the car kit draws 150mA and makes a hiss but the radio does not work in it - maybe because the battery is missing?

Jon_G4MDC · 18th Jul 2021, 10:04 am

9.6V is correct. 8 x 1.2V Nicads were in the pack. There is a fuse under a sliding cover which is part of the battery connection gubbins on the base of the set.

Schematics of the modules were never available only an interconnection diagram. Unlike most P5000 modules you can't get in the ceramic coated ones to fix them. If they are faulty they are scrap.

137MHz sounds like Gas/Electricity was the original user. You are right it's NBFM only with direct FM of the crystals on TX. If it is A1 Band then it's a good prospect to convert to 2m amateur band, most were A2 and needed capacitor changes to get the RX front end to tune. At least that module can be worked on.

Station X · 18th Jul 2021, 10:06 am

Some basic info here:-

https://www.radiohistory.uk/PF85broc.htm

JulietMike · 18th Jul 2021, 12:21 pm

I have a pdf of the service manual. PM your email address.
Regards, John

davidw · 19th Jul 2021, 8:54 am

If its transmitting 137Mhz then its a B1 which is 132-146Mhz, according to page 148 of the late Chris Lorek's second PMR conversion book.

Jon_G4MDC · 19th Jul 2021, 10:29 am

Thanks for the reminder of rather rusty memory. Of course it was..
It even says so in the brochure linked by Graham in post#3

18th Jul 2021, 9:56 am	#1
jimscoper Triode Join Date: Jun 2020 Location: Yalding, Maidstone, Kent, UK. Posts: 35	PYE PF85 - schematic - info Picked up a PF85 plus car kit and lapel mike at boot fair - without battery. Applied 9 volts and it behaves like a radio and puts out about 137MHz and draws about 170mA on PTT. Now wondering what to do with it. Basically looks like a conventional NBFM radio. To do much with it would need to alter the LO and disable the squelch. Made a bit more difficult by the mysterious OM601, 603, 602 and 605 modules. Are schematics available? And what was the 'proper' battery voltage and how long the 'rubber duck'? BTW, the car kit draws 150mA and makes a hiss but the radio does not work in it - maybe because the battery is missing?

18th Jul 2021, 10:04 am	#2
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: PYE PF85 - schematic - info 9.6V is correct. 8 x 1.2V Nicads were in the pack. There is a fuse under a sliding cover which is part of the battery connection gubbins on the base of the set. Schematics of the modules were never available only an interconnection diagram. Unlike most P5000 modules you can't get in the ceramic coated ones to fix them. If they are faulty they are scrap. 137MHz sounds like Gas/Electricity was the original user. You are right it's NBFM only with direct FM of the crystals on TX. If it is A1 Band then it's a good prospect to convert to 2m amateur band, most were A2 and needed capacitor changes to get the RX front end to tune. At least that module can be worked on. Last edited by Jon_G4MDC; 18th Jul 2021 at 10:16 am. Reason: Banding corrected to match the spec brochure which follows!

18th Jul 2021, 12:21 pm	#4
JulietMike Tetrode Join Date: Dec 2012 Location: Andover, Hampshire, UK. Posts: 85	Re: PYE PF85 - schematic - info I have a pdf of the service manual. PM your email address. Regards, John

19th Jul 2021, 8:54 am	#5
davidw Heptode Join Date: Sep 2006 Location: Woodbridge, Suffolk, UK. Posts: 643	Re: PYE PF85 - schematic - info If its transmitting 137Mhz then its a B1 which is 132-146Mhz, according to page 148 of the late Chris Lorek's second PMR conversion book. __________________ Dave G1AGK. My perception is my reality!

19th Jul 2021, 10:29 am	#6
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: PYE PF85 - schematic - info Thanks for the reminder of rather rusty memory. Of course it was.. It even says so in the brochure linked by Graham in post#3

18th Jul 2021, 10:06 am	#3
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: PYE PF85 - schematic - info Some basic info here:- https://www.radiohistory.uk/PF85broc.htm __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.