Is there any possibility of modifying the docking station to supply power to the TC64? I have the TC64 v1, and for my standalone use cases, it would be really nice to not have to use the breakout cable since it's a bit cumbersome and sticks out pretty far. Plus it would be nice to reduce wear on the breakout cable and its connector.
Modify docking station to supply power?
- PaulSlocum
- Thread is Unresolved
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Don't Panic. Please wash hands.
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You mean just by using the cartridge connector?
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Jens should confirm this first, but i think it could work if you provide +5VDC at pin 2/3
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Did it to my docking station. Works fine
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Feeding in power is possible at the joystick ports, the A500 keyboard port and the Minimig connector. However, a word of caution: Chameleon V2 has a mechanical protection of using the power-USB port when plugged into a C64 that prodives it with power. Since the Docking station does not have a metal shroud, the power-USB connector is accessible, letting you connect two power supplies at the same time.
So if you're making this epectrical modification, I suggest to also add a mechanical part that will cover the power-USB port of Chameleon V2, so even if you are unpacking the unit after weeks or months of non-use, something screams at you "remove any connector from this port". A simple 90-degrees bent metal part should do the trick; the black base plate is just wood and accepts self-tapping screws ("Spax").
Chameleon V1 has a Schottky diode in the cable loom that addresses this problem, but adds new challenges to the USB power supply, which is why I have resorted to the mechanical solution on V2.
Jens
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Here is the end result. Added a power switch aswell
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If I feed in power through the joystick port, is it still okay to use a 5.2V USB supply? I find that most of my USB power supplies are 5.2V.
That's still OK - mostly because the cables are dropping a bit of voltage when loaded. The Chameleon itself is fine with voltages up to 5.5V, but that's an "absolute maximum rating" that may result in permanent damage when operated for extended preiods of time. You won't be able to touch this level with a 5.2V USB PSU.
I have the Turbo Chameleon version 1, and when I use a 5.2V USB power supply with the TC64 breakout cable, I measure only 4.5V on the joystick port. Is this normal? I assume it's normal because of the schottky diode, but I just wanted to make sure since that's lower than I expected.
This is indeed more voltage drop that I'd expect. The schottky diode should NOT drop a full 0.7V when loaded with about 440mA (that's about 420mA from the Chameleon and another 20mA from the Docking Station). The drop should be more in the 0.45V area. I suspect that there's a few weak link in the path from PSU to the Docking Station - or a pretty hefty voltage drop in the PSU itself.
Jens
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That's still OK - mostly because the cables are dropping a bit of voltage when loaded. The Chameleon itself is fine with voltages up to 5.5V, but that's an "absolute maximum rating" that may result in permanent damage when operated for extended preiods of time. You won't be able to touch this level with a 5.2V USB PSU.
Do you think an Amiga keyboard connected to the docking station is going to be okay at 5.2V? I made a USB to 9-pin dsub power cable for the docking station (which I haven't hooked up yet) and I measure 5.2V at the end of the cable, so there's not significant voltage drop on the cable.
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Do you think an Amiga keyboard connected to the docking station is going to be okay at 5.2V?
Yes. THe controller chip is a MOS6570, which has an absolute maximum rating of 7V.
I made a USB to 9-pin dsub power cable for the docking station (which I haven't hooked up yet) and I measure 5.2V at the end of the cable, so there's not significant voltage drop on the cable.
You've measured voltage without load, not voltage drop. You can only measure the drop if you load it. I'm pretty sure that the reading will be different once you have everything connected that you intend to.
Jens
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I really don't want to rain on your parade, but "testing" is different from "trying" in engineering terms.
A test usually involves research about the parameters under which a device needs to operate in the field, resulting parameters that need to be verified and checking for acceptable/non-acceptable failure modes. In this case, a real test would involve recording the voltage at the source, at the destination and measuring the current that's going through the cable in order to cross-check with the maximum acceptable parameters from the cable manufacturer, all while at least checking for changes in the EMI spectrum in order to see if the original CE declaration from iComp can still be applied. This is just the electrical part - on top of that, there's temperature, humidity and things like "what happens if someone trips over the cable?" - this "tripping" part is actually the reason why so many power cables are using DC jacks that are easily pulled out, and Apple went for the magnetic connectors.
So while I'm happy that it works for you, I'd like to point out for anyone else that this is just a single data point confirming that it's fundamentally possible to supply the Chameleon/Docking station duo through the joystick ports, but it's an engineer's setup that needs to be verified locally. Again, please don't take this personal; there's a liability insurance covering our products, which probably turns down a claim if your house burns down and someone points to your setup as being the root cause of a fire.
Jens
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The last reply was more than 365 days ago, this thread is most likely obsolete. It is recommended to create a new thread instead.
