Heathkit FM-3 tuner rebuild

[rh2music]

Anyone have suggestions or know how to restore an old FM tuner? Heathkit FM-3 hasn't been plugged in or tested, original condition, looks good. thanks

[EWBrown]

http://www.dynaco-doctor.com/#DYNACO%20 ... IC%20TUNER

THe first link (scroll all the way down to FM-3) has the full instruction manual in PDF format for free download and printout

http://www.audiokarma.org/forums/showthread.php?t=82780

http://www.audiokarma.org/forums/showth ... 780&page=2

Have some pictorial "how-tos" for the FM3 mods and upgrades

Should get you started.

Usualy there may be some weak tubes, dry electrolytics, and some of the ceramics (caps and PECs) may be flakey, and a general alignment may be needed.

/ed B

[Tom Bavis]

Ed, there was a HEATH FM-3 as well as the Dyna... I assume that's what he's asking about. Quite a compact package, and not easy to work on, I'm afraid... I have one that needs some attentoion, which it hasn't received yet... The schematic for the FM-3A is online at http://www.vintage-radio.info/heathkit/index.htm

[snitch56]

I'm confused! Yellow_Light_Colorz_PDT_09
Is this your tuner?
http://www.heathkit-museum.com/hifi/hvmfm-3a.shtml

[kheper]

Anyone have suggestions or know how to restore an old FM tuner? Heathkit FM-3 hasn't been plugged in or tested, original condition, looks good. thanks

Do you have the original assembly manual? Having it on hand will make things much less painful.

I have one of these FM-3a units. But, figured it was more trouble than it was worth fixing. I was assured the unit was entirely functional, so I turned it on and - nothing. Then, I pulled the case and got zapped. Be careful. Since the unit is packed with components, there is high voltage - literally - running everywhere.

The FM-3a is mono, but you can tap off the signal before the audio stage and run this output to an MPX decoder for stereo.

Probably all the caps need replaced. You should 'soft-start' the unit to try to reform the caps and take voltage readings, as per the manual, to determine what needs replaced.

http://hhscott.com/cc/1st_soft_start.htm

I do not know how these Heathkit tuners are aligned. The tuner kits were designed to allow amateurs without scopes and tone generators to align them. Once you change a cap or a tube, in the IF or RF section, it will probably need a realignment.

[EWBrown]

I guess I got too much Dynaco on my mind Yellow_Light_Colorz_PDT_09

Hence my AA and Bottlehead moniker of "Dyna Saur"

/ed B

Dunno much about the Heath FM-3, other than I gutted out a really "wrecked" free one for the power trannie and a few parts, it was too far beyond redemption to attempt an overhaul...

Similarly I have 3 more of the old Eico FM tuners that I got for dirt cheap, tw are beyond redemption, possibly the third one can be "safed" glory halleluiah, pass the soldering iron Yellow_Light_Colorz_PDT_04

THe memory is the second thing to "go" and I forgot what the first thing was Yellow_Light_Colorz_PDT_09 :o Yellow_Light_Colorz_PDT_04

/ed B