Michael A. Terrell wrote in message
m...

radio10 wrote:

I think the MAX406 is an op-amp.


Low power precison op amp

http://datasheets.maximintegrated.co...406-MAX419.pdf


I think the LT508 1298 might be a A-D converter but I can't find any
info other than a vague reference. I was hoping this was an Opto.


PWM & PFC?

http://www.datasheetarchive.com/LT508-datasheet.html#


There is a 93LC46 which I believe is a PROM.


1K EEPROM 128 x 8- or 64 x 16-bit organization

http://ww1.microchip.com/downloads/e...doc/21712b.pdf


Then there's the PIC16C57 28 pin device.


http://www.datasheetcatalog.org/data...hip/30453d.pdf


All seems potentially OK, ie display works, voltages appear as expected.

The fault seems to be the switching of the heating element which is
locked ON all the time.

However I notice there is nothing happening and no change to MT1 on the
triac during any state including forcing the temperature sensing.

I can see DC levels varying on the temp pot.


Most of these ICs are obsolete.


Sounds like a severe case of KISS