seadzz
Active Member
Well I just completed the modification of my TU717 per the guidelines over at the TIC website. I thought I’d share the results of the work with folks here.
I put this project off a number of times due to fears of fooling with the dial string. Let me start by saying it is far easier to do then the instructions there would lead you to believe. The biggest problem is accessing the F2680 PCB which is mounted to the front panel and requires you to remove the dial string to wiggle the board out of its mounting. If you take your time and do not force things you need only remove the string from one pulley. I rotated the tuner to one end of the dial, removed the faceplate and popped the string off the rearmost pulley. You need not do anything more to the string just leave it there. You will then need to shoehorn it out but rest assured it comes out.
For the selection of components I used Panasonic FC electrolytic’s for all positions except where Mylar film caps were called for. Sansui engineers used a couple of Mylar (polyester) caps on the audio board (F2680) and I used Panasonic Polypropylene ECQP(Z) 1pf as something of an upgrade. You need to be careful when selecting replacements for these two caps (C01 & C02) because there is not too much free space on this board.
Fortunately there is a great deal of free space when it comes to replacing the electrolytics. You can easily use 50 to 100V caps in all locations except C11 and C12 on the F2680 board. The OEM caps are 6.3V and I don’t think anything larger than a 35V will fit.
AS for the results I am pleased. I suspect that there is not too much audible improvement in replacing the power supply caps but I do feel changing the diodes in the power supply to Schottk’s gave me some. I also feel all the work on the audio board was worth the effort. Since we are still well within the break in period I will reserve judgment on the overall value of the effort but so far so good. Another point worth passing on is you need not remove any other PCB’s from the tuner. Only the F2680 needs to come out, all others can be worked on while still attached to the sheet metal.
You may want to consider this project if you have a TU717 or similar and have a few days worth of free time. As a point of note, you absolutely need a service manual for this project. Good reading glasses and or a magnifying glass is also helpful as some of these traces and pads are getting a mite small.
sdz
I put this project off a number of times due to fears of fooling with the dial string. Let me start by saying it is far easier to do then the instructions there would lead you to believe. The biggest problem is accessing the F2680 PCB which is mounted to the front panel and requires you to remove the dial string to wiggle the board out of its mounting. If you take your time and do not force things you need only remove the string from one pulley. I rotated the tuner to one end of the dial, removed the faceplate and popped the string off the rearmost pulley. You need not do anything more to the string just leave it there. You will then need to shoehorn it out but rest assured it comes out.
For the selection of components I used Panasonic FC electrolytic’s for all positions except where Mylar film caps were called for. Sansui engineers used a couple of Mylar (polyester) caps on the audio board (F2680) and I used Panasonic Polypropylene ECQP(Z) 1pf as something of an upgrade. You need to be careful when selecting replacements for these two caps (C01 & C02) because there is not too much free space on this board.
Fortunately there is a great deal of free space when it comes to replacing the electrolytics. You can easily use 50 to 100V caps in all locations except C11 and C12 on the F2680 board. The OEM caps are 6.3V and I don’t think anything larger than a 35V will fit.
AS for the results I am pleased. I suspect that there is not too much audible improvement in replacing the power supply caps but I do feel changing the diodes in the power supply to Schottk’s gave me some. I also feel all the work on the audio board was worth the effort. Since we are still well within the break in period I will reserve judgment on the overall value of the effort but so far so good. Another point worth passing on is you need not remove any other PCB’s from the tuner. Only the F2680 needs to come out, all others can be worked on while still attached to the sheet metal.
You may want to consider this project if you have a TU717 or similar and have a few days worth of free time. As a point of note, you absolutely need a service manual for this project. Good reading glasses and or a magnifying glass is also helpful as some of these traces and pads are getting a mite small.
sdz
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