Homebrew PCBs

Yea... the AL9 was a real mindbender..... having the two parrallel 
thermal switches
and
the shorting out of the indicator lights circuit.



On 12/31/2016 07:35 PM, Harvey Altstadter hrconsult@... 
[Homebrew_PCBs] wrote:
>
> 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
>
>
> On 12/31/2016 1:31 PM, Rob roomberg@... [Homebrew_PCBs] wrote:
>>
>> 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
>>>>>
>>>>
>>>
>>
>
>