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Rob,
It looks like it is similar to the Apache that you have, but it lacks the second thermoswitch mounted directly on the heater. I don't understand the wiring in parallel of the two thermoswitches in your schematic. I assume that they are normally closed, opening on reaching their specified temperature. Since they are in parallel, and wired in series with the heater, the only one that would have any effect would be the higher temperature one. I could understand if they were in series. Then the lower temperature switch would be the controller, with the higher temp switch acting as a protection in case the lower temperature switch failed short. The effect on the green light would be the same as it is in your description.
The HF unit has an additional thermoswitch mounted on the heater in a thermally insulating mount. That switch is normally open, and is in series with the resistor, rectifier and the green LED, and turns on the ready light when the unit has reached temperature.
The HF unit is also somewhat larger, with a larger heater assembly. The rest is empty space.
Harvey
thanks
I had not seen that dimmer hack yet.
Those pictures show the guts of the laminator.
Looks a lot like my APACHE AL9
http://www.learnmorsecode.com/laminator/al9.html
http://www.learnmorsecode.com/laminator/gbc/index.html
On 12/31/2016 02:38 PM, Harvey Altstadter hrconsult@... [Homebrew_PCBs] wrote:
Rob,
The Harbor Freight unit is "concentric" in the sense that the heat is provide from all around the roller assembly. It is not concentric with either roller. There are two heaters mounted on opposite sides of the rollers, and an aluminum structure that is manufactured to fit around the rollers. The aluminum structure is actually two pieces that are separated to form the slots for the paper path.
The BOM for this unit is mostly irrelevant. By the time the mod is done, not much of the original circuitry or wiring remains. The temperature control thermoswitch is removed,and replaced by the temperature controller I referenced yesterday, the thermal switch that controls the ready light is removed because it operates at a temperature that is irrelevant. What remains is the small circuit board that holds the ready LED and the power indicator LED, and the ON/OFF switch. This board has two rectifiers, two resistors and two LEDs. The motor remains, the heaters remain and the thermal fuse remains.
There are some photos of the interior of the laminator here: https://www.flickr.com/photos/15304611@N03/sets/72157635447779272/ This mod is one that adds a dimmer in series with the motor, so most of the pics have to do with modifying and mounting the dimmer, but there a few that show the motor, the heater and the circuit board. The heater control thermoswitch is on the underside of the heater assembly, and not in view in these pics.
Harvey
On 12/31/2016 11:10 AM, Rob roomberg@... [Homebrew_PCBs] wrote:
Really? This grabs my attention.
What make and model?
Can you take a picture and share?
Is there an online parts list we can eyeball that shows how concentric heaters are mounted?
On 12/31/2016 11:53 AM, 'David C. Partridge' david.partridge@... [Homebrew_PCBs] wrote:
But, but the heaters are concentric with the rollers (or at least they are in my laminator) so
stopped/forward/reverse should make no difference.
Dave