Vintage 1980s Amercep Turbo Solderer Iso-Tip knockoff Teardown - Page 1
Forum section: electronics / general

author: GnatGoSplat
author_rank: Regular Contributor
timestamp: August 05, 2020, 11:18:42 pm
content: Youtube recommended I watch bigclive's Iso-Tip soldering iron teardown from over 5-years ago.It reminded me that I have this dead Amercep Turbo Solderer, an Iso-Tip knockoff from the 1980s. It was sold by DAK Industries. As a kid in the 80s, I didn't read comic books or whatever else kids back then were into, I read the DAK Catalog. At some point, I managed to convince my mom to buy it for me, guessing I was around 10 or 11.This is what the kit looked like. The transformer melted the power brick and died on the original dock, that was the first time the iron died. The one in the photo is a replacement I got for free. Power brick is DC6V 0.2A. It also came with a car charger that I've never used.It had an incandescent bulb that is just visible in this photo. It also could stand on its end, though it would fall over if the table is bumped.3 screws and it's open without much fuss. 2 solder-tab SANYO CADNICA Ni-Cad batteries, KR-1300SC 1300mAh. Decent brand, this must have been before cheap no-name batteries. These are both shorted, is the reason the soldering iron has been dead for the past decade or more.Fully removed from the plastic casing. It just lifts right out. The terminal blocks for the tip have set screws to hold the tip and wires in.Closeup of the PCB. The charging circuit is super simple, very similar to a real Iso-Tip except it's in the iron instead of the dock. Just a 15-ohm series-resistor and a 220-ohm series resistor for the LED.The car charger DC barrel jack is missing, because it melted. For some reason, they ran full current to the tip through the detect switch in the jack. This was the 2nd time this iron quit on me. I ended up fudge-fixing it by removing the jack and shorting across the detect switch solder pads.Internals flipped around, and also showing the bulb. 5mm style bulb with leads that just touch the exposed tip terminal block things when the plastic bulb-holder is slid into place.Foil side of the charging PCB. You can see where I jumpered across the solder pads for the DC jack detect switch. The red wire is for some reason soldered to the underside even though there was a hole drilled for it on the top side.Inside view of the dock. Dock connector is a 3.5mm mono audio-style jack.Car charger. Nothing in it but a power resistor to drop the current.Couldn't figure out why they ran the ground terminal for the tip through the barrel jack detect switch. As bigclive said in his video, these tips can peak at 20A, and I don't think the detect switch in a barrel jack is designed for that. Decided to draw up a schematic to see if it becomes more clear, but I still can't figure out the reason for doing that. Other that, very simple like a real Iso-Tip charging circuit. LED is driven in kind of a weird way as well, running off the difference between charger voltage and battery voltage.I really liked this soldering iron back in the day, but both tips that came with it went bad after a few years. Some point in the 90s, I discovered Iso-Tip tips are identical and fully compatible, so I got a few more years out of the iron before it quit charging and I stored it away.Now, I'm thinking to bring it back to life. Iso-Tip battery packs probably fit it (measurements check out), and I think I can retrofit a standard barrel jack since I can't find the original type that was in it.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 07, 2020, 02:14:49 am
content: Quote from: GnatGoSplat on August 05, 2020, 11:18:42 pmFit in a R/C type high current lipo and a USB input for charging. You can also add a MOSFET for PWM control and maybe even sense the tip resistance to do temperature control.

author: GnatGoSplat
author_rank: Regular Contributor
timestamp: August 11, 2020, 02:12:15 pm
content: Strange, the inline images worked when posted, but seem to be broken now.Quote from: NiHaoMike on August 07, 2020, 02:14:49 amGreat ideas, can't seem to find an R/C type high current lipo in cylindrical form though. Temperature control is probably far beyond my capabilities, unfortunately.I'd thought about Li-Ion or NiMH conversion, but bigclive's assessment of why they still use NiCd makes me think that might be better for the high current drain.On the other hand, Iso-Tip's website says their next gen will use LiFePO4, of which I think a 26650 could fit. It'd probably need PWM control in that instance.