Hi all,

I'm in the process of repairing a 3 phase inverter (variable freq drive, 1p=
h 240VAC=20
in, 3ph out) for one of my customers, one chip that needs replacing is prov=
ing=20
difficult to identify - it has the part number deliberately sanded off. I'v=
e nearly=20
exhausted all other avenues, though it would be worth a quick query of the=
=20
collective minds here to see if anything rings a bell. Clues:

- Position in circuit is after an ST6562T65C6 8 bit micro, before a 74HC14 =
hex=20
inverter and IR2133J 3 phase bridge driver. It seems the function of this c=
hip would=20
be to produce 6 x sine PWM signals (high and low side signals for 3 phase b=
ridge),=20
under control of the micrcontroller.
- 28 pin DIP package
- A very small area of the logo remains visible, a circle made up of square=
 dots, eg=20
Allegro Micro Systems or similar.
- 5V DC power to pin 25
- GND to pins 11 & 16
- 8MHz clock to pin 10 (from ceramic resonator, shared with microcontroller=
)
- About 9 control lines from micro
- 6 outputs, pins 13,14,15,17,18,20 feeding directly to 74HV14 hex schmitt =
inverter=20
then on to IR2133J 3 phase bridge driver and 3 phase bridge using discrete=
=20
MOSFETs.
- Hand written label R050008 suggests it may be programmed, eg. another=20
microcontroller or a PLD etc.

I've contacted a company that say they can repair the board, but I'm waitin=
g on=20
confirmation they can supply this chip, repair approx USD500. A replacement=
 board=20
is >USD3000. Can't easily replace with an off the VFD because of a propriet=
ary=20
interface, perhaps serial.

Thanks~!

--=20
Brent Brown, Electronic Design Solutions
9 Titoki Place, Pukete,
Hamilton 3200, New Zealand
Ph: +64 7 849 0069
Fax: +64 7 849 0071
Cell: +64 27 433 4069
eMail:  brent.brown@clear.net.nz



--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.