UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Heathkit IT-12 Signal Tracer

tim.norris · 14th Apr 2019, 12:37 pm

I purchased this from across the pond last year as they seem to be somewhat rare over here and therefore tend to command high prices . The only problem being that it is 110v this was negated by the purchase of a 240/110 converter from the Maplins closure sale for a bargain price. On arrival it was found to be in reasonable condition cosmetically apart from the grille cloth had turned to dust . a wrong knob and the probes red tip was in a poor state . Internally it was very clean and someone had made a good job of wiring /assembly . I swopped out various out of tolerance resistors and the capacitor to the output tube a.12ca5 was replaced. I intended to restuff the smoothing capacitor but i ended up having to leave off the alloy cover due to a miscalculation on my part ! I didn`t like the idea of the probe lead traioling over the bench so swopped this out for a bnc connector .easily reversible. Forum member David G4EBT kindly turned a new probe end cap from a piece of Acetal rod i provided . The probe was rebuilt with a new ceramic capacitor installed and the diode tested ok and a new length of 50ohm rg58 coax terminated with a bnc connector. a new power cable fitted and two similair knobs from Cricklewood electronics which were a good fit on the imperial shafts .While shopping in Aldi (other supermarkets are available) i spotted some Aida cloth used for cross stich embroidary that looked perfect for the speaker grille cloth .Its quite stiff and perfect for sticking to the remaining grille frame. On power up the unit worked well apart from the magic eye a 1629 valve was like me not very bright ! and some strange intermittent rustling/crackling noises when the volume was increased. A replacement 1629 was obtained and after a lot of head scratching the noise fault turned out to be a badly microphonic 12Ax7 dual triode valve which was replaced with a nos russian equivelant .These are used in guitar amps and are getting somewhat expensive. Reasembled and cleaned it not only looks well but works well . Next up is a Heathkit capacitor tester . Regards Tim

14th Apr 2019, 12:37 pm	#1
tim.norris Hexode Join Date: Feb 2012 Location: Blackburn, Lancashire, UK. Posts: 282	Heathkit IT-12 Signal Tracer I purchased this from across the pond last year as they seem to be somewhat rare over here and therefore tend to command high prices . The only problem being that it is 110v this was negated by the purchase of a 240/110 converter from the Maplins closure sale for a bargain price. On arrival it was found to be in reasonable condition cosmetically apart from the grille cloth had turned to dust . a wrong knob and the probes red tip was in a poor state . Internally it was very clean and someone had made a good job of wiring /assembly . I swopped out various out of tolerance resistors and the capacitor to the output tube a.12ca5 was replaced. I intended to restuff the smoothing capacitor but i ended up having to leave off the alloy cover due to a miscalculation on my part ! I didn`t like the idea of the probe lead traioling over the bench so swopped this out for a bnc connector .easily reversible. Forum member David G4EBT kindly turned a new probe end cap from a piece of Acetal rod i provided . The probe was rebuilt with a new ceramic capacitor installed and the diode tested ok and a new length of 50ohm rg58 coax terminated with a bnc connector. a new power cable fitted and two similair knobs from Cricklewood electronics which were a good fit on the imperial shafts .While shopping in Aldi (other supermarkets are available) i spotted some Aida cloth used for cross stich embroidary that looked perfect for the speaker grille cloth .Its quite stiff and perfect for sticking to the remaining grille frame. On power up the unit worked well apart from the magic eye a 1629 valve was like me not very bright ! and some strange intermittent rustling/crackling noises when the volume was increased. A replacement 1629 was obtained and after a lot of head scratching the noise fault turned out to be a badly microphonic 12Ax7 dual triode valve which was replaced with a nos russian equivelant .These are used in guitar amps and are getting somewhat expensive. Reasembled and cleaned it not only looks well but works well . Next up is a Heathkit capacitor tester . Regards Tim Attached Thumbnails