[S Clark]

I've pulled the board from a Victor turntable TT-81 after blowing a fuse.  Since it is early 80's electronics, I pulled all the electrolytic capacitors awaiting replacements from Digikey.  While it's on the kitchen table, I decided to reflow the solder joints.  I have no idea what solder was used back then, but when I reheated the joints, if they needed a bit of extra, I used some Cardas eutechtic.  I've found one site that insist that all old solder should be replcaed, stating that surface oxidation would be mixed in and create problems as it cooled.  I guess it could happen, but seems like overkill to me.  Have I screwed up by reflowing the solder in the old joint?  Also, almost all of the carbon resistors are still pretty close, but a 1.5K measures 1.2K.  Should I replace it? 
There are lots of guys around here that have slung a lot more solder than I have, so I'm hoping to learn something from the collective knowledge here. 
Scott

[Folsom]

The resistor was probably 1.2kohm new. That is unless it was under high stress. I doubt that.

I wouldn't worry too much. If the parts were about keeping RF transmission integrity you might have to do better.

[S Clark]

Any thoughts about reflowing the solder in the joints?

[randytsuch]

If that was my project, I wouldn't worry too much about the solder joints. 
As long as they look ok, should be fine.

Signal doesn't actually go through them, so as long as the speed tracks and the fuse doesn't blow, I'd call it good.

[Folsom]

You could wipe a little flux on all of them before reflowing, or add a tiny bit of solder.

[Steve]

I've pulled the board from a Victor turntable TT-81 after blowing a fuse.  Since it is early 80's electronics, I pulled all the electrolytic capacitors awaiting replacements from Digikey.  While it's on the kitchen table, I decided to reflow the solder joints.  I have no idea what solder was used back then, but when I reheated the joints, if they needed a bit of extra, I used some Cardas eutechtic.  I've found one site that insist that all old solder should be replcaed, stating that surface oxidation would be mixed in and create problems as it cooled.  I guess it could happen, but seems like overkill to me.  Have I screwed up by reflowing the solder in the old joint?  Also, almost all of the carbon resistors are still pretty close, but a 1.5K measures 1.2K.  Should I replace it? 
There are lots of guys around here that have slung a lot more solder than I have, so I'm hoping to learn something from the collective knowledge here. 
Scott

Hi Scott,

I am glad you use Eutectic solder, preferably quad. This is much stronger, more sonically accurate than other solders.
From that aspect, I would clean off the old. However, cleaning off the old and using quad will alter the sonics, a consideration, but then some parts are most likely out of tolerance anyway. Depends upon where the 1.5k resistor is located.

I have performed a lot of special listening tests of projects, and with superior parts and design, have found the quad Eutectic solder the most accurate/natural. (Tri tends to grow tentacles over time, that tend to short out to other wires/foils.)

Cheers and good luck on your project Scott.

steve

[S Clark]

I never thought about the soldier's sonic signature with this being a turntable.  Surely there would be no change since its not in the signal path.  And yes, I was using the Cardas quad.  If I ever do something like this again, I'll remove the old solder first. 
Thanks guys.

[Steve]

I never thought about the soldier's sonic signature with this being a turntable.  Surely there would be no change since its not in the signal path.  And yes, I was using the Cardas quad.  If I ever do something like this again, I'll remove the old solder first. 
Thanks guys.

Seeing the complexity of the pc board, at least 8 adjustments, I figured the board contained at least the phono stages, with RIAA equalization etc. If the board is just to control the motor, and no musical signal stages, use whatever you like.

Cheers, hope all works out ok.

steve

[timind]

Steve, I'm so glad you came back with this reply. I was wondering why you were saying the sound would change as this is a control board.

For Sclark, did you reflow the joints on the ICs?

[Steve]

Steve, I'm so glad you came back with this reply. I was wondering why you were saying the sound would change as this is a control board.

For Sclark, did you reflow the joints on the ICs?

I am glad I checked back Timind. Wow, that is some complicated board for just a motor control. Seems way too complicated, carbon/carbon film resistors no less, but it works, so I am telling myself, don't knock it. I guess that was the technology in those days.

cheers

steve

[S Clark]

Steve, yep, that board is for speed control.  The Victor TT-81 was next to the top of the line for Japanese Victor in the early 80's- building units to compete with the Technics SP-10s. 
Timind- nope I left the IC's alone.  Those were dainty little solder joints and I figured best left alone. 

Parts came in today, so I hope to report back tomorrow with a working table.  Several of the caps from Digikey are soooo much smaller for the same value.  The 1000uF 16V caps are probably less than half the size of the 1981 caps that were in it.  I tried to use Panasonic FM and FC when values were available. 

[FullRangeMan]

Any thoughts about reflowing the solder in the joints?

Hi Steve, just now see this your topic, please note usually the solder of a PCB as this were made all at once in a large hot solder welding tray, the parts heat absorption were minimal.

Redo 1 or 2 bad solders is possible, but redo all the solder joints by hand is a sensitive task, the hand solder heat the componets for a long time (30/60 seconds). If the solder was printed its even harder.

A nice option to good looking a PCB is the cleaner spray:
https://www.ebay.com/itm/SPRAY-CLEANER-WASTE-IN-CIRCUITS-PCB-TASOVISION-250ML/332829128227?hash=item4d7e297623:g:phsAAOSwx~pbXv2p:rk:6:pf:0
This is a contact cleaner:
https://www.ebay.com/itm/Electrical-Contact-Cleaner-Switch-Clean-Spray-Circuit-Board-Terminal-Car-Auto/352535659084?hash=item5214c3424c:g:68cAAOSwoVZcBT9w:rk:15:pf:0

[Steve]

Hi Steve, just now see this your topic, please note usually the solder of a PCB as this were made all at once in a large hot solder welding tray, the parts heat absorption were minimal.
.........

I think you meant to address Scott FRM, since you are quoting him?

cheers and great weekend FRM.

steve

[S Clark]

All caps are in, new fuse in place.  One issue of note... a cap value in the repair manual is not the same as what was on the board.  The manual called for a 33 uF 25V when the cap on the board was a 3.3 uF 25V.  Since the TT was working properly before blowing a fuse, I assume that the manual is wrong and the correct cap was on the board.  All electrolytic caps on the board were replaced with caps of equal value, although many are much smaller in size.   

Regardless, put it all back together and still no power.          I'll let it sit for a few days and start over. 

Update: Couldn't stand it.  Had to go back to it.  Poked around looking at power, fuse good, but seemed a bit loose in the holder.  With a bit of squeezing with a pair of needle nose, I'm in business!!!!   Reassemble after dinner, and testing for the rest of the night.