I fear the worst surf 1.2

[Metalmatt]

I'm not sure if this is in the correct section but I could do with some
help regarding my surf 1.2.
While sorting out my shielding I inadvertently connected my coil wires together
and fear I have damaged a component. The audio is now a constant low hum with
no pickup with the battery pack heating up.
Can anybody shed some light on this unfortunate situation?
This site has helped me enormously and I feel I've messed up at the last minute.
many thanks

[homefire]

What test equipment do you have ? First thing I would do With the coil un connected is check is if the IRF 9640 is still switching. My bet is it's toasted. Check and see if the Driver NE555 is still singing. That's about all that would get fried. Easy Fixes. I've never done stuff like that ! LOL

[Metalmatt]

Thanks for your reply.
The mosfet irf 9640 installed is y64k BG.
ive got a y56k BC....
any thoughts?

[homefire]

Don't know those Fets. N channel over a few hundred volt 5 or more amps should do the job I would think.

[Metalmatt]

Thanks for your reply but surely you mean a p channel mosfet?!?

[homefire]

Oooopa. Yes P channel.

[Ferric Toes]

Thanks for your reply.
The mosfet irf 9640 installed is y64k BG.
ive got a y56k BC....
any thoughts?

IRF9640 is the correct part number. The other numbers and letters are manufacturer's batch and date codes and are of no relevance. IRF9640 is -11A, 0.5 ohms Rds and -200V Vds.

Eric.

[Goaty]

Hi metalmatt,
not too sure how experienced you are with working on pc boards but a word of warning about desoldering components may be timely.
I have found that it is very easy to damage the pads and tracks on these boards when removing components, but have found a couple of techniques which can reduce the chances of damage.
With the double sided boards just using a solder sucker or solder wick on all of the component leads often results in pulling pads off the board and stripping the through-hole plating out as well when trying to wiggle the component free.
I have had more success, with less board damage, by melting the solder on all of the component pads at once until it comes free and can be gently pulled out. The pads and holes can then be cleaned up with a solder sucker or solder wick. If the pads for the component are close enough together they can all be melted at once by bridging across them all with the well tinned tip of the soldering iron. This can often be made easier by bridging them all with a large blob of molten solder.
If the component being removed is not going to be reused then all of its leads can be snipped off and then individually removed by melting the solder.
A temperature controlled iron is also a big help in reducing board damage - too hot and the pads will lift, too cool and the component will be damaged by being heated for too long while waiting for the solder to melt.

Hope this helps

[Qiaozhi]

A simpler less damaging method is to simply cut the pins off the device, and solder the new component onto the stub that's left. This works fine for 2 and 3 pin components. For IC's, you can cut off all the pins and desolder them one at a time. After that I always fit an IC socket. Of course, it's easier to fit an IC socket in the first place.

[kosacid]

@Goaty best way is a hotair station if you have one and if your going to reuse the component, other than that cut the legs of use your solder sucker big tip coming here lol
see the heat shrink you get put a bit on the end of your sucker, it can take a lot of heat also you get a good vacuum and no chance of it bouncing of the board

[Metalmatt]

Thanks for all your helpful replies. It turns out that I fried both the irf and 555 by shorting the two coil
wires. Andy (silverdog) put me straight after an evening of Q and A. Few days later via eBay alls good in da hood!
Thanks to all who helped me out!

[homefire]

What test equipment do you have ? First thing I would do With the coil un connected is check is if the IRF 9640 is still switching. My bet is it's toasted. Check and see if the Driver NE555 is still singing. That's about all that would get fried. Easy Fixes. I've never done stuff like that ! LOL

LOL I think I heard that before.

[Goaty]

Glad to hear you got it working again Matt.