Pics often help when trying to diagnose problems.
Hi,
Yes, I know, sorry. I’ve been working on this one all day, and so haven’t had time to do pics. Plus it’s a vanilla driver. It looks like this one:
I found a solder point on the emitter side where the Vbatt appears (the two vias between the FET legs in that pic), so I’ve moved the emitter+ wire to that point, but still no light. I’ve also put a scope on the MCU pin 5, the PWM output and it’s at ground/0V, so I think that the MCU must’ve gotten borked somehow. I’m trying to find another one that I’m willing to swap.
Jim
I think that I’ve proved to myself that it’s the MCU that is bad. I found another spare working EAST-092 and swapped the MCU to the non-working driver and it started working. Also took the MCu from the non-working and put it on the working and that still doesn’t work.
Re-did the swaps and now the originally-working spare is working and the originally non-working one is not working. I guess I’ll just keep the non-working one, but without the MCU, as spare parts.
Thanks,
Jim
Way to go.
Actually, I’ve been wondering if it’s possible to swap in an Attiny13a for the EAST-092 MCU?
Maybe with cutting and re-routing some of the traces and pins?
Has anyone done that? Besides getting this particular board working again, I have several more EAST-092 drivers and some extra ATTINY13A chips and would love to put my own firmware on them with the EAST-092s!!
I don't know if anyone has done that. There are several low cost boards available that make MCU swaps much easier for that type of FET in 17mm board such as these:
https://oshpark.com/shared_projects/eD4kRUiO
https://oshpark.com/shared_projects/lCBkc8G6
https://oshpark.com/shared_projects/IHvO85FY
I guess you have seen this thread by now.
I probably should’ve explained the reasons for what I was asking: I have a bunch (a small bunch) of original EAST-092 boards, including the now-non-working ones, and the reason for my question is two-fold: (a) to try to get the non-working one working again (if I could use an ATTINY13A instead of the original PIC MCU) and if I can do “(a)”, then (b) I could do the same MCU swap for the rest of the EAST-092 boards so I can use different firmware.
So basically, the now-dead EAST-092 gives me incentive to try this if it’s possible with “no risk” since it’s already dead anyway…
I will probably try this at some point, when I get enough time…
EDIT: I think that this is a schematic for the “vanilla” EAST-092. This is from an old thread and was provided by Tivo I think:
I think that this is a generic schematic for NANJG with ATTINY13A:
It seems like the Vcc and GND on the EAST-092 board would need to be re-routed to support the ATTINY13A, and also the PWM output would need to use pin 6 instead of pin 5.
I’m not sure about the voltage divider/voltage reference though. I had asked earlier about minimum components for an EAST-092 and was told that the voltage divider is only needed for low-voltage checking (LVP), so possibly I could just leave that pin disconnected?
What I’d probably do to test is to reflow the ATTINY13A onto the EAST-092 board, but with the pins that I want to re-route bent upwards, and then solder those to where I want them to go using wirewrap wire, at least for a test/proof-of-concept?
Does that sound like it might work?
It would certainly make a good learning project. It’s up to you to decide if it’s worthwhile. I’ve done a bit of trace gerrymandering myself.
Hi,
Here’s what I’m thinking of. I’ve already prepared a new ATTINY13A for this:
No need to justify doing this. I just meant to provide you some info you may have missed while you are away. It was thinking like above that had you and Tivo way ahead of us all back when you two were working on developing FET+7135 drivers.
With the info you gathered and presented above, it does look doable. I think the easiest way would be to do the following:
- Remove old MCU and old voltage divider resistors.
- Cut a piece of Kapton tape and put it over the Pin 8 pad.
- Cut a piece of Copper tape to make a trace that goes from Pin 1 pad to over Pin 8 pad.
- Solder the tape to Pin 1 pad and tin the part of the tape that is over Pin 8 pad.
- Cut a piece of Kapton tape and put it over Pin 1 pad.
- Solder in your Attiny13a
- Run a solder blob from Pin 4 to the Ground ring.
If you do the above right, you will still be able to reflash the MCU in the future. You will need to change the PWM output pin in your FW from Pin 6 (PB1) to Pin 5 (PB0).
Best wishes on your endeavor. I really enjoy doing stuff like this. Please keep us posted.
Hi,
I just got it working!! I love it when “theory meets reality” :)!! Plus, I will be able to re-program these EAST-092s!!
For this first one, I did it slightly differently… I forgot about trying to be able to re-program the MCU later, so your procedure will be better in the future.
I’ll post some pics in a bit, with info for what I did.
EDIT: Some pics:
Lit - lowest mode with FET and minidrv - kind of a bright moonlight mode:
The earlier drawing with notes on what I did:
Here’s the steps I did:
1) Cut the trace from MCU pin 1 that goes to the diode and cap.
2) Remove the diode and bridge it
3) Bend pin 8 of the new ATTINY13A-SSU MCU up and flux and pre-tin it
4) Cut the trace leaving pin 5 to the FET Gate pin
5) Reflow the new ATTINY13A-SSU MCU
6) At same time, remove R3 and R4 (the resistors for the voltage divider)
7) Bridge the MCU pin 4 to the ground ring
8) Jumper wire from the cap to MCU pin 8
9) Jumper wire from MCU pin 6 to the FET Gate pin
I think that was all…
Jim
EDIT 2: I forgot to mention:
- I’m using an AOD510 FET for this driver, instead of the original FET.
- I had to solder the emitter+ wire to the via holes that are between the FET legs because I wasn’t seeing V+ on the original emitter+ pad (some kind of defect on the board I think).
Nice work. I need to get some of that fine wiring you used there. Do you happen to know anything about that stuff you are using?
I have tried the wires from telephone extensions and such, but the insulation just melts off when soldered.
Hi,
It’s 30AWG, Kynar, Silver coated wire, available in different colors:
http://www.amazon.com/Jonard-Industries-R30G-0100-Coated-Silver/dp/B00IKDI35I
If you use this type of wire, you’ll need a stripper that can strip 30AWG. I use the stripper part of this tool instead:
ImA4Wheelr,
I will try something closer to what you suggested today on another EAST-092, but slightly different. I don't have any copper tape, so:
Remove ...
.
.
Run a solder blob from MCU Pin 4 to the Ground ring.
I was tempted by your suggestion to modify the firmware to use a different port for the PWM but at the end, would rather not have to maintain another FW version for the EAST-092 vs. NANJG boards. If the above works, I'll try to do an in-circuit programming and see if that works. Thanks! Jim
EDIT: What I wrote above is WRONG! I think that ImA4Wheelr's steps are ok, but I don't have copper tape so will have to do something different, but the steps I wrote are not correct when trying to do this combining my original steps with his, without copper tape (NOTE: my original steps where I cut traces does work).
I think that ImA4Wheelr's steps take advantage of the copper tape being insulating to the surface underneath the tape and conductive/solderable on the surface on top of the tape. I haven't used copper tape before myself, so I'm not sure but that seems like the assumption.
Thank you for the wire and wire cutter info and links. I'm going to get them as I do a good bit of driver air wiring myself.
Your latest approach sounds good to too. Are you thinking of soldering the wire on the inside part of the pins so that it won't interfere with connecting to a programming clip?
I wasn't banking on the adhesive on copper tape being an effective insulator. Especially after being soldered. The Kapton tape is for insulation. The adhesive was just to hold the trace in place until it was soldered to the Driver Pad 1 and MCU Pin 8. I suggested tape because it is thin and won't lift the MCU pins too much.
EDIT: I see you edited your post. I think you idea will work fine if you solder the wire to the inside of the legs. Opps. No, you're right. That won't work. A thin piece of wire can be used in place of copper tape.
I’m getting close to trying this with the wire still. The new board is prepared I think/hope, and just burned the firmware into the new MCU. This time, I basically (a) cut the traces around pin 8, then (b) ran a small wire between pads for pins 1 and 8.
I also cut the traces around pad 5 (I don’t particularly like using the kaptop tape… the space are TINY!! But I think that I’m going to have to use it to cover pad 1.
I think the question is going to be if MCU will still reflow with that wire between pins 1 and 8 and with the kaptop tape on pin 1.
Now I have to put a piece of kaptop tap on pad/pin 1 before doing the MCU reflow.
EDIT:
Ok, it works, but not exactly as I originally planned:
Parts removed:
I cut the traces around pin 8 pad (NOTE: when cutting traces around pin 8 pad, you have to cut two traces. One is to the left of the pad and the other connects the pad to the via on the right. Both the connection going to the left and that connection to the via on the right has to be cut.) and around pin 5 pad, then added a wire shorting from the Vcc+ to the cap and then to MCU pin 1 and pin 8 pads (not all those joints are needed, but the way the wire ran it was just easier):
Put a small piece of kaptop tape over MCU pin 1 pad then added some solder paste to the pads then reflowed the MCU:
I soldered wire from MCU pin 6 to the FET GATE pin. I tried to solder to the MCU pin as close to the board as I could, to allow the SOIC8 clip to still work.
I also bridge pin 4 of the MCU to the ground ring using solder:
The driver works (lights) and I have the modes I set in minidrv (this is moonlight - bright moonlight):
I tried connecting the MCU to USBASP programmer. The Pomona 5250 clip I have wouldn’t work, mainly because I think when I reflowed the FET, it was too close to the top of the MCU. I can fix that later, but I tried a cheap SOIC8 clip I bought from Amazon, and it worked:
So, overall, the EAST-092 MCU conversion worked and also I can still program the MCU in-circuit :)!!
Hi,
I just realized something: Fasttech still sells A version of the EAST-092:
From the pics on their website, that looks like the same design as the ones I have, so that means that it should be possible to convert the FT EAST-092s to ATTINY13A the same way?
Would this be a better way to get a cheap, programmable FET driver than doing the NANJG-92 route? I mean you wouldn’t have to be removing 7135s, mounting the FET upside down, and sanding the corner off of the FET?
I just tried to put one of the modified drivers into a light (an TR-F2) and when I test using a power supply it seems to work (I have modes, etc.) but when I tried with battery in the light, it looks like it killed the tailcap switch?
What I mean by “killed” is that the tailcap switch no longer clicks!!
I actually tried a 2nd tailcap, and it did the same thing (stopped clicking).
Can too much current make the switch stop clicking?
The thing is when I test on the bench supply, it looks like it’s only about 2.85 amps at 4.2V. Would that be enough to damage the switch so badly that it’d stop clicking?
Thanks,
Jim
I was able to scrounge together parts from a SolarForce clicky switch to work in the TR-F2 tailcap, and it’s working now, so I’m pretty sure the original switches melted due to current. So now I have a TR-F2 with a forward switch and with the converted EAST-092 driver running minidrv with 6 modes.
Pretty cool :)!!
Nice work Jim! Regardless of how useful it is use an East92 as a basis for a custom FET driver (it does look useful, and prettier than a 'nanjg92') I think it is great that you tested the options :-)