Like New Nautilus Exercise Bike has Dead Panel

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

yes. Basically there are different voltage rails for different IC's to work. So, you got some thing like: 5V, 3.3V, 2.5V and 1.8V.
1st pin is power input, 2nd pin is GND and the 3rd pin is power output.

OK, I'm going to hook it back up, plug the adapter in and take the readings for each of the ICs and report back.

BTW, do those P/Ns look right? Curious what they tell you.

[CapLeaker]

Re: Like New Nautilus Exercise Bike has Dead Panel

[QUOTE=vestaviascott;848289]Awesome. Here are the P/N's:

RG1 = 3940M3 501434L


RG2 = GH16D 4266J2
https://cdn.badcaps-static.com/pdfs/...27ae2b3e9b.pdf

RGA1 = 3940M3 501434L
see RG1

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

For RG1, voltages are from left to right:
.8 (left pin)
7.2 (middle pin)
8.72 (right pin)

For RG2, voltages are from bottom to top:
8.93 (bottom pin)
.2 (middle pin)
4.98 (top pin)

For RGA1, voltages are from left to right:
8.9 (left pin)
.6 (middle pin)
4.99 (right pin)

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

Interesting, as I was testing the connections at a couple random times, I heard a couple long tone beeps (just like I would expect to hear when the panel fires up). I can't be certain if they were coming from the DMM or the bike. I glanced over at the panel and saw no signs of life so its likely it was something else beeping near me. The DMM was on the DV voltage switch (not beep mode) so I don't know how it could have come from there.

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

yes. Basically there are different voltage rails for different IC's to work. So, you got some thing like: 5V, 3.3V, 2.5V and 1.8V.
1st pin is power input, 2nd pin is GND or ADJ and the 3rd pin is power output.

So, aside from the consistant 5V reading, my voltages are way different than it appears you are expecting:

For RG1, voltages are from left to right:
.8 (left pin)
7.2 (middle pin)
8.72 (right pin)

For RG2, voltages are from bottom to top:
8.93 (bottom pin)
.2 (middle pin)
4.98 (top pin)

For RGA1, voltages are from left to right:
8.9 (left pin)
.6 (middle pin)
4.99 (right pin)

What does this tell you or what should it tell me? If these are acceptable voltages what's the next step to isolate the problem?

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

I suppose when comparing RG1 and RGA1, since they are the same P/N, I should expect similar voltage readings? That would lead me to think that RG1 may be defective. Its output voltage (assuming its the right pin) 8.72 reading is above the expected 5V output I'm seeing on the reference doc PDF.

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

Some additional notes on the Voltage measurements:

For RG1 (3940M3), voltages are from left to right:
.8 (left pin = Vin)
7.2 (middle pin = GND)
8.72 (right pin = Vout)

For RG2 (GH16D), voltages are from bottom to top:
8.93 (bottom pin)
.2 (middle pin)
4.98 (top pin)

For RGA1 (3940M3), voltages are from left to right:
8.9 (left pin = Vin)
.6 (middle pin = GND)
4.99 (right pin = Vout)

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

Updated readings as of this morning:

For RG1 (GH16D), voltages are from left to right:
0.7 (left pin - GND)
7.2 (middle pin - Vout) * I measured this several times b/c I was expecting 5 V
8.7 (top pin - Vin)

For RG2 (3940M3), voltages are from bottom to top:
8.9 (bottom pin = Vin)
0.1 (middle pin = GND)
4.99 (right pin = Vout)

For RGA1 (3940M3), voltages are from left to right:
8.9 (left pin = Vin)
.6 (middle pin = GND)
4.99 (right pin = Vout)
[/quote]

So, for RG1 and RGA1, the voltages appear normal and expected, correct?



So, from the chart, assuming this is the 5v version, I'm guessing since this bike calls for a 9 Volt power supply, the pin readings should be:

Pin 1 (input): No more than 16 volts (expect appx 9 volts due to 9 volt power supply adapter)
Pin 2 (Ground): appx 0 volts
Pin 3 (output): 5 volts

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

So, based on my readings, is it correct to conclude that the RG1 voltage regulator is leaking voltage to the board and is likely cause of the failure? Expecting 5v, Actual observed is 7.2

For RG1 (GH16D), voltages are from left to right:
0.7 (left pin - GND)
7.2 (middle pin - Vout) * I measured this several times b/c I was expecting 5 V
8.7 (top pin - Vin)

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

Yes, but what likely role would a switch THERE serve in such a device? (Goal is to have OP think about why "it" would care about whether the power adapter was mechanically attached -- or not!)

Since gray wire is coming from the speed sensor AND the power supply, perhaps the switch in this case is to automatically allow the console to "sleep" when there is no activity (measured by the speed sensor) for a period of time.

Then, when the user gets back on the bike and engages the pedals, triggers the speed sensor (gray wire lead) and the console switches on.

I'm guessing on that obviously, but that's my experience with exercise equipment is that they typically have a sleep mode for inactivity and in this case it needs some means to "wake" which the speed sensor could obviously inform.

[CapLeaker]

Re: Like New Nautilus Exercise Bike has Dead Panel

Updated readings as of this morning:

For RG1 (GH16D), voltages are from left to right:
0.7 (left pin - GND)
7.2 (middle pin - Vout) * I measured this several times b/c I was expecting 5 V
8.7 (top pin - Vin)

For RG2 (3940M3), voltages are from bottom to top:
8.9 (bottom pin = Vin)
0.1 (middle pin = GND)
4.99 (right pin = Vout)

For RGA1 (3940M3), voltages are from left to right:
8.9 (left pin = Vin)
.6 (middle pin = GND)
4.99 (right pin = Vout)

So, for RG1 and RGA1, the voltages appear normal and expected, correct?



So, from the chart, assuming this is the 5v version, I'm guessing since this bike calls for a 9 Volt power supply, the pin readings should be:

Pin 1 (input): No more than 16 volts (expect appx 9 volts due to 9 volt power supply adapter)
Pin 2 (Ground): appx 0 volts
Pin 3 (output): 5 volts

Well... Now I don't know what regulator is which since you switched RG1 and 2 around with the part numbers. The GH16D LDO should have 3.3V output and you have something like 0.8V the rest goes to GND. The input voltage is sagging a bit due to this. So this LDO is bad. Does this regulator get a bit warm?

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

Well... Now I don't know what regulator is which since you switched RG1 and 2 around with the part numbers. The GH16D LDO should have 3.3V output. So this LDO is bad. Does this regulator get a bit warm?

Sorry about that, the post #51 IS CORRECT. in my original post I misidentified RG1 and RG2 (I'm used to linear numbering from left to right and these are out of sequence on the board which I lazily got backwards in my original post ID'ng the chips).

To clarify, RG1 is at the top of the board and is the lone GH16D chip. RG2 and RGA1 are both 3940M3 chips.

I'll check RG2 to see if it gets hot. Based on the observed voltages, is it possible that this could be the sole cause of the dead panel?

Can RG2 be replaced on the board?

[CapLeaker]

Re: Like New Nautilus Exercise Bike has Dead Panel

Depending on your soldering skills, yes RG2 can be replaced. As for me, I'd have no problem changing that (I do have a hot air rework station). It could be the cause for the dead panel, yes. Could be also that there is more broken. However, fix that what you know is broken first. In this case a new GH16D LDO.
Here: https://www.digikey.ca/products/en?keywords=AZ1117C
they have over 20.000 in stock. You need the 3.3V one.

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

...The GH16D LDO should have 3.3V output and you have something like 0.8V the rest goes to GND.

The readings in Post #51 are accurate. Please disregard all prior readings:

For RG1 (GH16D), voltages are from left to right:
0.7 (left pin - GND)
7.2 (middle pin - Vout) * I measured this several times b/c I was expecting 5 V
8.7 (right pin - Vin)

The input voltage is sagging a bit due to this. So this LDO is bad. Does this regulator get a bit warm?

Yes, after about a minute of the device being plugged in, this regulator is extremely hot compared to the others.

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

Depending on your soldering skills, yes RG2 can be replaced. As for me, I'd have no problem changing that (I do have a hot air rework station). It could be the cause for the dead panel, yes. Could be also that there is more broken. However, fix that what you know is broken first. In this case a new GH16D LDO.
Here: https://www.digikey.ca/products/en?keywords=AZ1117C
they have over 20.000 in stock. You need the 3.3V one.

Thanks! So, this one, correct?

https://www.digikey.ca/product-detai...ICT-ND/4505206

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

You need the 3.3V one.

OK, can you let me know how I should know whether its 3.3v or not? I was thinking 5volt.

I'm going to go ahead and order backups for the two 3940M3 chips while I'm at it - I'm already paying $4 bucks for shipping. What voltage are those?

[CapLeaker]

Re: Like New Nautilus Exercise Bike has Dead Panel

Yes, this is correct you need the 3.3V one, GH16D tells you that. I figured that this regulator should get a bit warm... lol. Replace it! Again the 0.7V on that regulator is the output voltage, not GND! Middle pin is GND! It is just that the regulator is bad and dumps the input voltage to GND.

You need a lot of heat (a good soldering iron or hot air) flux and solder to get this regulator of the PCB.

The other 2 regulators are 5V

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

Yes, this is correct you need the 3.3V one, GH16D tells you that. I figured that this regulator should get a bit warm... lol. Replace it! Again the 0.7V on that regulator is the output voltage, not GND! Middle pin is GND! It is just that the regulator is bad and dumps the input voltage to GND.

You need a lot of heat (a good soldering iron or hot air) flux and solder to get this regulator of the PCB.

The other 2 regulators are 5V

Thanks. I'll be having these soldered on by a friend who can do it. I'll practice on lesser projects.

[CapLeaker]

Re: Like New Nautilus Exercise Bike has Dead Panel

Let us know the outcome!

[vestaviascott]

Re: Like New Nautilus Exercise Bike has Dead Panel

Again the 0.7V on that regulator is the output voltage, not GND! Middle pin is GND! It is just that the regulator is bad and dumps the input voltage to GND

I was just going by this chart in the PDF that was referenced. In these shots, ground is pin 1 left, am I mis-reading? Just trying to learn as I go: