Homebrew PCBs

There are a number of large components on the Circuit board near the 
connection point to the fuser.  Several, what I believe are solid 
state relays - a triac w/heatsink (I think), some transformers etc.

The optocoupler I am not sure of.  There are a number of opto-
switches (the slotted devices used to sense something between 
them).  I don't think this is what you are referring to though so I 
will study the PCB some more to see if I Can find something that 
looks like an Optoisolater chip.  

On the fuser itself, there are the power wires going in one end of 
the unit.  On the opposite end, there are two groups of wires going 
in - I am assuming one of those two sets of wires is the 
thermostat.  I didn't want to mess with it too much till I found out 
what I should be keeping and such.

The unit seems to accept a PCB board without trouble and by turning 
the shaft by hand, it will pass right through.

I do have a photo-type thermometer that I use all the time around 
the shop - goes up to 400 degrees F so that should work good.  I 
will have to scrounge a motor somewhere.  It is winter here now so 
the retailers have all the grill stuff packed away - but, with 
Christmas getting close, as soon as that is over, the summer stuff 
will be back on the shelves again.



 
> There must be a triac in there and a optocoupler, which are 
useful. But  
> you could also use any solid state relais to make the thermostat. 
If you  
> follow the power wires of the fuser (the ones that go to the lamp 
inside  
> the roller) those will lead you to the interesting PCB. Also keep 
the  
> thermistor with the fuser (two thin wires coming out of it). You 
just need  
> to keep the thermistor with the wires, the electronics using it 
are  
> usually no good.
> 
> For a motor i use a chicken grill motor. Mine is a belt-drive with 
about 2  
> to 1 ratio, but direct drive would be OK, especially with the 
smaller  
> diameter rollers of a fuser.
> 
> I have the schematic for the simple thermostat somewhere, i'll dig 
it  
> out...
> 
> You'll want some type of thermometer that can measure the 
temperature of  
> the hot fuser roller to set it up, i suggest a thermocouple sensor 
on a  
> multimeter with temp. range or maybe a optical thermometer 
(although i  
> dunno how well they work on the fuser surface).
> You can use browning of paper and stuff, but it's really better to 
know  
> for sure.
> 
> ST
>