FIXED! Scotch Thermal Laminator TL901 won't heat up. 11¢ triac fixed the problem!

Scotch Thermal Laminator TL901 would not heat up. I concluded the 4A triac which controls the heating elements had failed. I replaced the 4A triac with an 8A triac. I bought 10 triacs on ebay for a little more than $1 DELIVERED. Get cash rebates for your many of your online purchases by using TopCashBack.
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[@tektech1065]

I would add that there are actually 6 screws in the bottom. The 4 under rubber feet, and two screws in deep holes closer to the center. One of these holes was covered with a white round "QC Passed" sticker.

[@tektech1065]

Excellent troubleshooting. Thanks for sharing the knowledge. I have the same laminator that had identical problem - a bad triac. It was heating up slightly, but never to the proper level and the "READY" green light would never turn on. The 4 Amp triac is underrated for a 3 Amp heater. I used BT138 - a12 Amp full size triac which I happened to have in my parts pile. I mounted it on the existing tiny heatsink after drilling a hole in it. That heatsink, by the way, is made of steel. I screwed the BT138 to it up side down, and ran cables from the 3 pins to the board. I left the old triac in place after cutting off the two legs and removing them off the PCB. It works great now! Takes 4 min. for 3 mil heat up, and 6 min. for 5 mil.

[@tektech1065]

This could help someone: My TL901 worked great after installing a much beefier BT138 TRIAC. But then, it stopped heating up again. I just replaced all five electrolytic caps and it works great again! I used caps pulled out of scrap boards. Caps are 105 degree, 470uF 25V, 220uF 25V, 100uF 10V, and 2x 10uF 50V, Use 16 or 25V 100uF instead of that 10V cap.

[@PeterLawton]

Job very well done.

[@donf3739]

So did the READY light come on after you stopped filming?

[@donf3739]

Does the "S" in 136S mean "short"? And can a longer one be trimmed off and used?

[@donf3739]

I just dug out my TL901 after having it stored for 15 years. When I turned it on it had that burnt electrical smell, and the green light didn't come on after 3 or 4 minutes. I ran the doc through anyway and it worked fine, but do you think the burnt smell is that same triac overloading?