Dandy Horse - no output

[Vivek_rc]

Hi All,

I had just powered up my Dandy horse and it was going well, was able to bias and got a nice flange. All going good, had it running in the blend mode and then suddenly there was a lot of static. And now my effected signal has no output and only get the dry signal when I flip the blend switch. I checked everything, voltages all look good and I followed the biasing steps again, clock frequency is set correctly. But now I don’t hear a signal on test Pad 6. I do hear a signal in test Pad 5. I’m connected SW1 and testing on a test box. So weird that it was working nicely and then boom...any help and advice would be appreciated








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Thanks

[Vivek_rc]

I audio probed and I’ve narrowed it down to around IC2.2, I don’t get any output from pin 10,11. Going into IC2.2 I can hear the effected signal on pin 15/14, but no output on  pin 11/10. I tried swapping the v571 I had on the aqua boy build and same outcome, no signal and no output on test pad 6. Chip itself is good and it works in the aqua boy. I also wired up the 3pdt switch just to rule that out.

Any advice would be greatly appreciated?


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[Scruffie]

Voltages por favor.

[Vivek_rc]

Voltages por favor.

Hi,

Thank you for your help,

These are the voltages I’ve captured. Something doesn’t look right on pin 7 of the v571.




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[Scruffie]

Well you've definitely pin pointed it to the correct area and you've checked it's not the chip so I suppose my only suggestions are to re-flow the solder joints around there and double check the values of R5 & 6.

[Vivek_rc]

I reflowed the area around IC2 and audio probed again, Checking the flow seems I’m not getting any output on pin 10 and 11 of IC2. I’ve swapped it out with the one I have in the aquaboy and Auquaboy works fine with v571. Also getting the expected voltages out of pin 10 and 11 but just  no audio....

[Scruffie]

Sorry, I should have read more thoroughly, I was talking about pin 7 of the 571, the voltage shouldn't be that low and that needs taking care of before you worry about output at pin 10.

[Vivek_rc]

I checked on the PIn 7 low voltage issue and I confirmed R5 and R6 are 47k and also reflowed the area, still getting around 2V on pin7.

[Scruffie]

What happens to pin 7's voltage if you remove IC1 from the socket? And the same for IC6.

[Vivek_rc]

Hey, back in business. I reflowed again all the components around ic2 and get a effected output now.. When I remove IC1 the voltage on pin7 is 6.8V. When I insert IC1 the voltage remains at 6.8V. Is that still too low a voltage or would it be ok?

[Scruffie]

6.8V is just fine Congrats on getting it going again.

[Vivek_rc]

Thanks so much for your Patience, help and support.

[Vivek_rc]

Hmmm.... seem to be back in the same position, where voltage on Pin 7 drops down to 2V. When I reflow the joints or clean up the solder joints with some alcohol, it starts to work, I get effected output and the voltage on PIN 7 sits around 6.8V, but I notice that as I leave it running the voltage on Pin 7 gradually starts to fall and once it gets down to 2V, just get a lot of static. Still trying to figure this out...? Hmm strange one. Could it be a defective Component around the pin7 region?

[Vivek_rc]

I replaced c29, c7, c12,r5 and r6 out of frustration and seems to have fixed the issues and flanging again, pin 7 of IC2 is sitting around 6.8V.  I’m leaving it run for a while to see how it fares . I had some weird readings earlier where pin 7 shot up to 14V. I cleaned up the solder side with a toothbrush and alcohol and Seemed to have stabilised now.

[Vivek_rc]

Coming back to the same situation, it runs ok for a while, all voltages check out but gradually pin 7 on IC2 starts to drop to 2V and then no output, no changes made just running it On flange mode through a looper...