FT102 -- vfo mechanical problem - UK Vintage Radio Repair and Restoration Discussion Forum

Ian G4HJM · 4th Nov 2007, 5:12 pm

Hi there,
I notice that the vfo knob, when rotated slowly and then released, sometimes turns itself back in the opposite direction by maybe a degree or so. Would a clean and lubrication session fix this or is it likely to be more serious ?

regards..
Ian

Sean Williams · 4th Nov 2007, 5:25 pm

A clean would be an excellent idea - go easy on the lube - shaft encoders do not work well when they are oily!

73
Sean
M1ECY

Ian G4HJM · 4th Nov 2007, 6:00 pm

Thanks for reply,
What do you suggest would be the best lubricant ?
I don't think I'll get any lubricant on the shaft encoder :->

regards
Ian

Sean Williams · 4th Nov 2007, 8:57 pm

Hi Ian,

You wont go far wrong using Servsiol switch cleaner and lubricant - might also be worth checking the dial tension setting (normally a screw adjustment accessible from the front panel)

Sean

Ian G4HJM · 7th Nov 2007, 7:15 pm

Thanks Sean,
Well the problem with the vfo has dropped down the priority list since a couple of nights ago i was tuning it up (as quickly as possible) and it went crackle, zzzzzzzzztttt, funny smell. Now when tuned up according to the instruction manual I only get about 80W key-down indicated on an external power meter instead of the 140W or so previously. Good hobby this -- LOL.

regards
Ian

Sean Williams · 7th Nov 2007, 9:20 pm

Ah, probably a flashover on the ACO board - there is a small relay on this board that is, to say the very least, unreliable! - this might well be knackered, as for 140w......, this power level is really flogging the guts out of an FT102 - three tubes in the PA wasnt really designed with higher output, more to aid reliability!

I have had some experience with these radios........

Cheers
Sean

Ian G4HJM · 8th Nov 2007, 8:14 pm

Thanks for the suggestions, I'll see how I get on.

Regards
Ian

Ian G4HJM · 2nd Dec 2007, 8:50 pm

Just returning to the vfo problem, you mentioned a dial tension adjustment, where's that ?

I've removed the vfo from the chassis to look at the scale illumination bulbs. I seem to have two different types fitted, neither have any current ratings printed on them. The one on the right is open circuit, I tried the left hand one, when powered by a 12V supply takes 30mA and gives a very feeble light. The parts list seems to suggest a 12V 100mA bulb, is that correct ?
http://www.greensgadgets.com/images/vfobulb.jpg

regards
Ian

4th Nov 2007, 5:12 pm	#1
Ian G4HJM Retired Dormant Member Join Date: Nov 2005 Location: Leicestershire Posts: 20	FT102 -- vfo mechanical problem Hi there, I notice that the vfo knob, when rotated slowly and then released, sometimes turns itself back in the opposite direction by maybe a degree or so. Would a clean and lubrication session fix this or is it likely to be more serious ? regards.. Ian

4th Nov 2007, 5:25 pm	#2
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: FT102 -- vfo mechanical problem A clean would be an excellent idea - go easy on the lube - shaft encoders do not work well when they are oily! 73 Sean M1ECY __________________ Engineers make things work and have spare bits when finished

4th Nov 2007, 6:00 pm	#3
Ian G4HJM Retired Dormant Member Join Date: Nov 2005 Location: Leicestershire Posts: 20	Re: FT102 -- vfo mechanical problem Thanks for reply, What do you suggest would be the best lubricant ? I don't think I'll get any lubricant on the shaft encoder :-> regards Ian

4th Nov 2007, 8:57 pm	#4
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: FT102 -- vfo mechanical problem Hi Ian, You wont go far wrong using Servsiol switch cleaner and lubricant - might also be worth checking the dial tension setting (normally a screw adjustment accessible from the front panel) Sean __________________ Engineers make things work and have spare bits when finished

7th Nov 2007, 7:15 pm	#5
Ian G4HJM Retired Dormant Member Join Date: Nov 2005 Location: Leicestershire Posts: 20	Re: FT102 -- vfo mechanical problem Thanks Sean, Well the problem with the vfo has dropped down the priority list since a couple of nights ago i was tuning it up (as quickly as possible) and it went crackle, zzzzzzzzztttt, funny smell. Now when tuned up according to the instruction manual I only get about 80W key-down indicated on an external power meter instead of the 140W or so previously. Good hobby this -- LOL. regards Ian

7th Nov 2007, 9:20 pm	#6
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,518	Re: FT102 -- vfo mechanical problem Ah, probably a flashover on the ACO board - there is a small relay on this board that is, to say the very least, unreliable! - this might well be knackered, as for 140w......, this power level is really flogging the guts out of an FT102 - three tubes in the PA wasnt really designed with higher output, more to aid reliability! I have had some experience with these radios........ Cheers Sean __________________ Engineers make things work and have spare bits when finished

8th Nov 2007, 8:14 pm	#7
Ian G4HJM Retired Dormant Member Join Date: Nov 2005 Location: Leicestershire Posts: 20	Re: FT102 -- vfo mechanical problem Thanks for the suggestions, I'll see how I get on. Regards Ian

2nd Dec 2007, 8:50 pm	#8
Ian G4HJM Retired Dormant Member Join Date: Nov 2005 Location: Leicestershire Posts: 20	Re: FT102 -- vfo mechanical problem Just returning to the vfo problem, you mentioned a dial tension adjustment, where's that ? I've removed the vfo from the chassis to look at the scale illumination bulbs. I seem to have two different types fitted, neither have any current ratings printed on them. The one on the right is open circuit, I tried the left hand one, when powered by a 12V supply takes 30mA and gives a very feeble light. The parts list seems to suggest a 12V 100mA bulb, is that correct ? http://www.greensgadgets.com/images/vfobulb.jpg regards Ian