Shazzam Tsunami Hydroflosser Repair - Page 1
Forum section: electronics / repair

author: Adler
author_rank: Regular Contributor
timestamp: June 10, 2013, 02:04:50 am
content: I picked up a hydroflosser on the cheap (broken, of course, my favorite). It has no power. I opened it up and found that its a pretty simple circuit.Two Ni-MH batteries, a motor, and a charging/managing circuit.Also, interestingly, this "Name brand" product seems to be a custom branded chinese piece of poop which casts doubt on the box's claims that it was invented by "celebrity dentist, Dr. Raymond Frye".I think the problem is D4, a diode I assume. This is where my expertise runs out though, what should I get to replace it? what size is this? do you agree that this is likely the cause? (I tested resistance in both directions and both were infinite)

author: c4757p
author_rank: Super Contributor
timestamp: June 10, 2013, 02:08:33 am
content: Quote from: Adler on June 10, 2013, 02:04:50 am"celebrity dentist". Hmmm... maybe I should reconsider my choice of professions.That's one odd-looking diode. Are you sure that's not an LED? I can't see it too well in the photo. If it's an LED it may as well test infinite - threshold voltage is too high for the meter.

author: David_AVD
author_rank: Super Contributor
timestamp: June 10, 2013, 02:11:22 am
content: Does you DMM have a diode test function? That would be a more reliable test than resistance.

author: Adler
author_rank: Regular Contributor
timestamp: June 10, 2013, 02:27:02 am
content: Quote from: c4757p on June 10, 2013, 02:08:33 amD1, D2, and D3 are LED's, pretty sure D4 is different.Quote from: David_AVD on June 10, 2013, 02:11:22 amThats a very good point. I should proabably have thought of that. In diode mode it settles at 0.945v in one direction and tests infinite in the other. That doesn't bode well for my diode theory, does it...

author: c4757p
author_rank: Super Contributor
timestamp: June 10, 2013, 02:32:42 am
content: No, seems like a perfect diode, though 950mV is a bit high.

author: David_AVD
author_rank: Super Contributor
timestamp: June 10, 2013, 02:41:37 am
content: Time to get back to basics; have you tested the battery and the motor ?

author: Adler
author_rank: Regular Contributor
timestamp: June 10, 2013, 02:44:42 am
content: Interestingly, when I bridge that diode (probably ill advised), the charging light starts blinking. Maybe 950mV really is too high?Quote from: David_AVD on June 10, 2013, 02:41:37 amI would expect some life from the LED's with a dead battery or motor. Maybe I expect too much. The batteries are quite dead right now but I bet this device works with no batteries at all, straight from the wall.

author: David_AVD
author_rank: Super Contributor
timestamp: June 10, 2013, 02:49:49 am
content: Depending on the circuit, drained batteries can pull the the main voltage rail down to the point where nothing works, even if it's on charge.

author: Adler
author_rank: Regular Contributor
timestamp: June 10, 2013, 03:09:27 am
content: Quote from: David_AVD on June 10, 2013, 02:49:49 amI tried disconnecting the batteries to rule them out. Nothing worked at all, including the blinking charge LED when I bridge D4. I don't think that rules out the batteries, so that is still an option. Not too easy to get 2.4v NiMH cells in this size, though.

author: David_AVD
author_rank: Super Contributor
timestamp: June 10, 2013, 03:10:59 am
content: Why can't you just wire in a temporary feed from a power supply? Just don't try to charge it of course.

author: Adler
author_rank: Regular Contributor
timestamp: June 10, 2013, 03:25:00 am
content: Quote from: David_AVD on June 10, 2013, 03:10:59 amThe main reason is that I have not yet obtained a universal power supply. I could always use a wall wart but I have a theory that may be simpler.Looking at these batteries, they look mysteriously like normal AA cells. There is printing on only one cell and it says 2.4v I am thinking that goes for both cells. I'm going to wire in a battery pack in parallel with some good NiMH cells.

author: Adler
author_rank: Regular Contributor
timestamp: June 10, 2013, 03:40:37 am
content: Battery pack in... it turns right on.It is still possible that the charging system is dead. But I think we have found the issue.Thanks for all your help and I apologize to the humble diode.

author: amyk
author_rank: Super Contributor
timestamp: June 10, 2013, 11:21:52 am
content: Welcome to the world of OEM... looks like Risun sell the RST5002themselves, andhere's another rebrand of the same thingwhich is probably much closer to their OEM price.(I'm still not entirely sure what this thing does though. Pressure washer for teeth?)

author: Adler
author_rank: Regular Contributor
timestamp: June 11, 2013, 03:55:22 am
content: Yup, pressure washer for teeth.Im not sure it is fixed yet. I charged the original batteries in an external charger and they seemed to hold a charge. So, I resoldered them in (I hate doing that, its always nerve-wracking soldering to batteries) and everything works. My cause for concern is that I plugged it in the charge about 4 hours ago and the light is still blinking, I guess I'll check it again tomorrow morning.

author: amyk
author_rank: Super Contributor
timestamp: June 11, 2013, 10:22:11 am
content: You can check the voltage on the batteries, it should be 1.4-1.6V per cell if they're being charged. If it's anything like an electric toothbrush the charger will be of the trickle type, so they will take a long time to charge.

author: Adler
author_rank: Regular Contributor
timestamp: June 24, 2013, 03:28:32 am
content: Well, unfortunately, this story isn't over. I left the unit charging for a day and it is now quite dead.I intend to attempt to draw up the circuit daveCAD style to better understand it when I have time, I think its just double sided. Any suggestions of where to start? I'm still thinking that diode looks funny...

author: David_AVD
author_rank: Super Contributor
timestamp: June 24, 2013, 04:25:20 am
content: Maybe it just needs new batteries?

author: amyk
author_rank: Super Contributor
timestamp: June 24, 2013, 11:21:20 am
content: Quote from: Adler on June 24, 2013, 03:28:32 amI'd start with the battery terminals.

author: Adler
author_rank: Regular Contributor
timestamp: June 24, 2013, 02:31:11 pm
content: Quote from: David_AVD on June 24, 2013, 04:25:20 amThe batteries charge in an external charger and hold a charge. I would think that indicates that they work, no?