Wanted Please. Decant PI board to replace the One in This enclosure.

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Shielding the pots will guard against electrostatic and electromagnetic fields affecting the internal pot tracks and by extension the circuit. Of course the front of the pots are shielded by metal chassis box which would also be grounded. Otherwise it makes no sense in plastic box. What do you think?

[kt315]

Yes, very good. Although the outer casing of pot is isolated from internals, they should be shielded I think, connected to virtual ground? Or battery? Not sure, will have to look at schematic.

with P-channel mosfet connected to cold end of coil - to minus.(bara, surf)
in case N-channel mosfet connected to cold end of coil - to plus. (dp, hh)

THIS RULE IS SIMPLE TO REMEMBER.

[6666]

Have a look at my Delta board. It's crazy, but it works. It was a labour of love. Never again will my love be so strong

wow love that wireing

my biggest project had nearly 2000 solder joints and it worked , NEVER NEVER again.

[dbanner]

Thanks for information KT. I am wobbly on shielding issues. Here is good document on the subject of shielding

[dbanner]

with P-channel mosfet connected to cold end of coil - to minus.(bara, surf)
in case N-channel mosfet connected to cold end of coil - to plus. (dp, hh)

THIS RULE IS SIMPLE TO REMEMBER.

So for Delta it is battery plus. And for surf and bara(p-channel MOSFET) it is battery minus. Good. No problem. Thanks

[dbanner]

Mu metal boxes for low frequency shielding? EMI/RFI plastic? This is new to me

[keith777]

Hi again guys.

could anyone point me in the right direction to buy a LF 357N Chip. i have been looking about the net/eBay for them. it looks like they all seem to come from china. not very promising after after reading some of the post on the thread.

also replacing the 1N4148 diodes. do i change them with newly bought 1N4148 diodes. or replace them with 1N4004 diodes.


thanks in advance guys.

[kt315]

check the diodes do not desoldering them from board -!
any simplest tester has special range for diode testing - look a sign 'diode' on it.

[6666]

could anyone point me in the right direction to buy a LF 357N Chip

It would be handy to find a reliable source of 357 chips, for a decent price.
They all come from china just gotta buy the real ones

[keith777]

anyone got a working one for sale.....

[keith777]

Hi again guys.

could anyone point me in the right direction to buy a LF 357N Chip. i have been looking about the net/eBay for them. it looks like they all seem to come from china. not very promising after after reading some of the post on the thread.

also replacing the 1N4148 diodes. do i change them with newly bought 1N4148 diodes. or replace them with 1N4004 diodes.


thanks in advance guys.

Hi again guys.

since this last post i have bought some LF 357N chips. here is some pics of the orignal one and the new ones.

when i took out the original chip. i had to pop it out and oops, some of the pins bent over and broke of f when i went to straighten then back up.
i tryied the new chips one at a time in the slot and the machine switches on but no sound/detecting etc out of it.
is the chips that i bougth the wrong numbers or something like that. i know they say LF 357N on them, but what about the other numbers etc on the chip what do they mean.

thanks in advance guys.

[keith777]

Hi again guys.

since this last post i have bought some LF 357N chips. here is some pics of the orignal one and the new ones.

when i took out the original chip. i had to pop it out and oops, some of the pins bent over and broke of f when i went to straighten then back up.
i tryied the new chips one at a time in the slot and the machine switches on but no sound/detecting etc out of it.
is the chips that i bougth the wrong numbers or something like that. i know they say LF 357N on them, but what about the other numbers etc on the chip what do they mean.

thanks in advance guys.

any advice on this one guys. it would be so much appreciated....

[6666]

Those other numbers are nothing to worry about they are things like batch numbers, date of manufacture stuff like that

[dbanner]

The first chip is definitely a fake. Lf357n is Texas instruments, national semiconductors, st electronics original. None of them look like your first chip. The second chips look like the real thing, but...... how can you be sure.
Did you check the diodes.

[dbanner]

The chips you purchased purported to be national semiconductors brand, they look fake also. Here is authentic National semiconductors brand. Notice the difference.