Voodoo Main Discussion

[Qiaozhi]

I decided to go forward with the Voodoo project but will probably start from scratch with a coil since I plastic shells everywhere.
Question for George.. What kind of lead wire from the coil to the box? I have used two shielded pairs for some project, others I have used a high quality USB2 cable. The only difference I have seen with past projects has been that the coil will balance at a slightly different place.
Don.

Here are the cables I've been using in various projects:

1. URM43 single-core ( very close to RG58 )
2. E383E 2-core
3. Flexible 4-core (type unknown)

[Qiaozhi]

Hiya George,,,I'm having a little problem with my build. I am getting +5v at TP14,,but I'm only getting 0.720v at TP15. I bought 2 x programmed PICs from Andy (Silverdog) and though I totally trust his programming skills I tried both PICs and still don't get the correct voltage at TP15. I re-programmed one of the PICS with the HEX you posted and still not getting the correct voltage at TP15. I have checked and double checked all the components I installed for correct placement and values,,I've checked for solder bridges and dry joints and I've totally cleaned my PCB. Could you tell me what I could try next please in the fault-finding? Should I try replacing the 79L05? The only different components I used were the FQT7N10LTF instead of the FQT7N10 which I couldn't find. Thanks, Regards, Marty.

There should be -5V at TP14, not +5V.
Assuming you meant to write -5V ... have you checked that there's a sync pulse from the PIC on TP9? This pulse clocks the LT1054 via Q5 and Q6. At the cathode of D6 there should be a voltage approaching +12V. This is then regulated by a 78L05 (U7) to provide +5V at TP15.
The FQT7N10LTF mosfets must be OK, otherwise you wouldn't have anything working.

[MartyJ1963]

Thanks George and Alec,,,Sorry, yes, I meant to write -5v,,,I haven't checked the Sync pulse yet on TP9 (Too many house repairs keep surfacing during my build) but I will check that this evening then post these results. Great 2nd Voodoo video Alec! Regards, Marty.

[MartyJ1963]

I took some scope shots of my sync signal at TP9. Do these look ok? Thanks, Marty.

[Qiaozhi]

I took some scope shots of my sync signal at TP9. Do these look ok? Thanks, Marty.

Yes, it's working.

[MartyJ1963]

Thanks George,,,Does that mean I don't have to worry about the voltage I checked on TP15? Am I able to move on? I just found a cable that may have 26 wires contained inside so 'll be able to measure and connect my LCD Cable if it has. Thanks, Marty.

[surfdetector]

Thanks George,,,Does that mean I don't have to worry about the voltage I checked on TP15? Am I able to move on? I just found a cable that may have 26 wires contained inside so 'll be able to measure and connect my LCD Cable if it has. Thanks, Marty.

Marty you need to be producing +5v before you can continue. Are you measuring ~+12v at the cathode side of D6?

[lamoiz]

hi Marty, do you find your fault? can you make us a picture of your pcb? we might be able to see the problem if there is an error ...

[MartyJ1963]

Hi Alec,,,No, I only have 8.42v at the cathode of D6. And still only 0.76v on TP15. Thanks, Marty.

[lamoiz]

take a picture of your circuit ...

[MartyJ1963]

Hi Lamoiz,,,I posted pictures of the power supply on page 15 post #352. Regards, Marty.

[lamoiz]

Hi Lamoiz,,,I posted pictures of the power supply on page 15 post #352. Regards, Marty.

are you on the value of r48? 10k?
brown black black red brown.

[Qiaozhi]

Hi Alec,,,No, I only have 8.42v at the cathode of D6. And still only 0.76v on TP15. Thanks, Marty.

Remove the 78L05 and measure the voltage at D6 cathode again.

[lamoiz]

oops I said stupidity, it is a 20k .. sorry ..

[MartyJ1963]

Hi George,,I removed the 78L05 and the voltage at the cathode of D6 is 9.89v. Thanks, Marty.