Pye PMR AM25B - UK Vintage Radio Repair and Restoration Discussion Forum

Denis G4DWC · 23rd May 2011, 11:05 am

Hi

Has anyone got a copy of the circuit diagram, or point me in the right direction for a Web link for the PYE AM25B or maybe the PTB10 Vanguard. This is the version with the Valve receiver. I already have a copy of the AM25T transistor receiver version.

Thanks

Denis

sentinel040 · 23rd May 2011, 1:13 pm

Dennis;

Somewhere in the pile file at home I have a copy of the manual for one of these beasts. I'm going to be out of the office tomorrow (at least) but if you dont mind waiting I will bring it in and either copy it or scan it, the later may be easier. Do you require just the circuit or the whole thing - that would have to spread out over a few days! Is it low band or high band?

Send me a pm if you like and let me know your requirements.

Regards

Ian (G8KSZ)

Denis G4DWC · 23rd May 2011, 5:57 pm

Hi Ian

Thanks for your kind offer. PM on its way.

Denis

Sparky67 · 24th May 2011, 5:40 pm

Hi Denis,

If you are going to run the AM25 one of the 'tricks of the trade' to improve the Tx audio was to s/c the choke and dis the two attached C's in the AF filter. Made a huge difference to the intelligibility. Same with the F27AM.

Probably made a small difference to the Tx spectrum as well

Cheers

Martin
G4NCE

Denis G4DWC · 30th May 2011, 11:29 am

That audio filter, Martin, was there to restrict the audio to the usual speech bandwidth and prevent higher audio sidebands straying into adjacent channels but as you say probably improved intelligibilty.

Ian has very kindly scanned and sent me the required parts of the manual for which I am most grateful.

Mods, the thread may be closed.

Denis

23rd May 2011, 11:05 am	#1
Denis G4DWC Pentode Join Date: Oct 2006 Location: Brackley Northamptonshire, UK. Posts: 240	Pye PMR AM25B Hi Has anyone got a copy of the circuit diagram, or point me in the right direction for a Web link for the PYE AM25B or maybe the PTB10 Vanguard. This is the version with the Valve receiver. I already have a copy of the AM25T transistor receiver version. Thanks Denis __________________ If you take something apart often enough, eventually you'll have two of them....

23rd May 2011, 1:13 pm	#2
sentinel040 Hexode Join Date: Feb 2007 Location: Near Lichfield, Staffordshire, UK, most of the time and Crystal Palace, S London, some of the time.. Posts: 330	Re: Pye pmr am25b Dennis; Somewhere in the pile file at home I have a copy of the manual for one of these beasts. I'm going to be out of the office tomorrow (at least) but if you dont mind waiting I will bring it in and either copy it or scan it, the later may be easier. Do you require just the circuit or the whole thing - that would have to spread out over a few days! Is it low band or high band? Send me a pm if you like and let me know your requirements. Regards Ian (G8KSZ)

23rd May 2011, 5:57 pm	#3
Denis G4DWC Pentode Join Date: Oct 2006 Location: Brackley Northamptonshire, UK. Posts: 240	Re: Pye pmr am25b Hi Ian Thanks for your kind offer. PM on its way. Denis __________________ If you take something apart often enough, eventually you'll have two of them....

24th May 2011, 5:40 pm	#4
Sparky67 Heptode Join Date: Feb 2008 Location: Great Barr, Sandwell, West Midlands, UK. Posts: 589	Re: Pye PMR AM25B Hi Denis, If you are going to run the AM25 one of the 'tricks of the trade' to improve the Tx audio was to s/c the choke and dis the two attached C's in the AF filter. Made a huge difference to the intelligibility. Same with the F27AM. Probably made a small difference to the Tx spectrum as well Cheers Martin G4NCE

30th May 2011, 11:29 am	#5
Denis G4DWC Pentode Join Date: Oct 2006 Location: Brackley Northamptonshire, UK. Posts: 240	Re: Pye PMR AM25B That audio filter, Martin, was there to restrict the audio to the usual speech bandwidth and prevent higher audio sidebands straying into adjacent channels but as you say probably improved intelligibilty. Ian has very kindly scanned and sent me the required parts of the manual for which I am most grateful. Mods, the thread may be closed. Denis __________________ If you take something apart often enough, eventually you'll have two of them....