lpc1 amp compatability

mb9513 · by **mb9513** » Sun Nov 20, 2011 9:24 pm

Hi Ron: i had a frind of mine Darell) post a question to you on the compatability of tsa1 amplifiers. sorry it was so confusing because he has a dh100. he has forwarded the replies from you to me as i have been working with him to get his juke restored. My Juke is lpc1, the tsa amp is dead on one channel. i got another one that had been recapped already, and it was dead on the same side. i have a chance to get a tsa5 that appeares to have new caps in it, and wonder if it will go in lpc1? after checking the schematics for both amps i can only see one connection change. pin 6 of the mute connector has a pin connection that tsa1 does not. i traced it through the mechanism schematic and it looks like it goes right through to the tormat selector. This is my first juke so i have got it working great, this is the last issue that it has now. the recapped tsa 1 i got, i have traced the problem to the red side power amp section by swapping the connections at c115 & c135 and then checked the output transformers by doing the same thing @ c140 & c120. i am at a standstill for now. so hope your insights will help. Darrell was very satisfied by your help. thanks Mark

by **Ron Rich** » Sun Nov 20, 2011 10:22 pm

Hi Mark,
In an emergency, with an adapter plug, the TSA-1 and 5 can be swapped. It is not recommended however, due to the fact that the -1 is built for a 16 ohm system, while the -5 was built for the specific 5 ohm system used in the SS-160 model. ( the 4th wire in the mech/mute plug is not used in any model phono--it was there for a factory test). TSA-1's and TSA-3's can be interchanged in 90 % of the instances without any problems. Ron Rich

mb9513 · by **mb9513** » Mon Nov 21, 2011 6:01 pm

Thanks Ron: So that puts me back to the origional problem of on channel out on tsa1. is there any specific componant i should be looking for in the power amp section. the service manual doesn't have any test points. thansk Mark

by **Ron Rich** » Mon Nov 21, 2011 6:14 pm

Mark,
Nothing "specific"--just need to check individual components, back from out-puts--
Ron

Unclep2k · by **Unclep2k** » Tue Nov 22, 2011 3:01 am

A handy way to troubleshoot audio amps and localize problem is a signal injector that can inject audio signals along path of amp starting at output tube and working back until you find a stage where signal won't pass. Another similar way is a separate audio amp with a capacitor coupled probe( to block dc) where you can listen for the normal input signal as it passes through amp.