| Author |
 Topic  |
|
|
Cameronhimself
Copper Member
11 Posts |
 Posted - 10/14/2008 : 03:18:05
|
Hey guys, so I am brand new to the forum and really just looking for some help. I purchased a Boss DD2 that was working until it got to me. Here is the info:
The unit powers on, passes signal both on and off, and the led comes on full strength but no delay effect is audible. I can hear a change in hum when I adjust the effect level but no other knob seems to make a difference (except the delay time/ hold knob which engages the hold function properly but with no delay).I opened the unit up and I did happen to find a resistor with a burned spot around the solder joints on the bottom of the board. Also, the resistor looked to have corroded posts. The resistor appears to be R59. I do have a multimeter but I haven't used it in 4 years and might need a refresher. Also, these issues happen with a battery and with a power supply.
Thanks so much in advance!
Cameron |
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/14/2008 : 06:10:44
|
Hi Cameronhimself!
R59 is in the "reset" circuit. If R59 is toast (open circuit), it could well be that the delay is "always off" - it's a pretty likely smoking gun.
Being "burned" is possibly not good... Although your description could also mean a simple dry joint (which is OK - it happens).
First step is to measure it with the power off and see if it reads 10k. If you have a soldering iron, redo the solder joints.
Let us know how you go... |
 |
|
|
Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/14/2008 : 09:07:52
|
Hi Cameronhimself
Welcome to the forum from Australia.
Looks like you are already in good hands, with Laurie...
Regards Dr. Bob |
|
|
|
Cameronhimself
Copper Member
11 Posts |
Posted - 10/15/2008 : 23:04:48
|
Thanks for the warm greeting guys! So I re-did the joints and measured across the resister and got 0000. I haven't taken electronics in at least 5 years, but I take that as a bad sign? Would this resister being bad cause the whole unit not to work?
Thanks!
Cameron |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/15/2008 : 23:10:49
|
Yep - it needs to read 10,000 Ohms ("10k"). Open (infinite resistance) or short (0 Ohms) will cause problems - it can in fact shut the entire unit down because it is in the reset circuit.
Please don't think I'm rude... but is everything in your measurement approach OK? (is the 0 Ohms reading real?) And is there a solder "dag" perhaps between the two pads of the resistor?
|
Edited by - Laurie on 10/15/2008 23:11:55 |
|
|
|
stahlhart
Platinum Member
1318 Posts |
Posted - 10/16/2008 : 23:27:36
|
| ...and was that resistor measuured in-circuit or out-of-circuit? |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/16/2008 : 23:46:02
|
quote:
Originally posted by stahlhart
...and was that resistor measuured in-circuit or out-of-circuit?
Should be roughly the same... If it is truly reading 0 Ohms in circuit, then something somewhere is shorted out. If it's not too much trouble, pull it out of circuit and measure it, plus measure across it's pads on the PCB with it out of circuit - that will tell us where the short is.
|
|
|
|
bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 10/17/2008 : 12:09:08
|
| Resistors usually break (infinity ohms) when they burn so if the PCB is fine with no solder shorts, I would suspect that something in parallel to R59 has shorted here. R59 sits between +9V and pin 5 on the BA634 circuit. If the BA634 has shorted, R59 would read 0 ohms. |
|
|
| |
Topic |
|
DD2 problem (first post here!)
