Hardware problem
Moderator: hvxl
-
- Starting Member
- Posts: 14
- Joined: Sun Aug 14, 2016 2:22 pm
Hardware problem
Hi,
Just constructed the OTGW and started with the diagnostics part (http://otgw.tclcode.com/debugging.html#power) to be sure everything is correct. The first check:
Check for 5V +/- 1% between pins 5 and 14 of IC1 and pin 15 and 16 of IC2
measures around 6.5V which is well above the set specs. Can someone help me out how to proceed?
Thanks,
Mark
Just constructed the OTGW and started with the diagnostics part (http://otgw.tclcode.com/debugging.html#power) to be sure everything is correct. The first check:
Check for 5V +/- 1% between pins 5 and 14 of IC1 and pin 15 and 16 of IC2
measures around 6.5V which is well above the set specs. Can someone help me out how to proceed?
Thanks,
Mark
Re: Hardware problem
The usual reason for a wrong Vcc is using the wrong voltage regulator, an LM78L05 (to-92) instead of an LM7805 (to-220). Otherwise the LM7805 may be bad or getting an input voltage that is too high (wrong transformer).
Schelte
-
- Starting Member
- Posts: 14
- Joined: Sun Aug 14, 2016 2:22 pm
Re: Hardware problem
Just checked and its a L7805CV, is this one correct?
https://goo.gl/photos/iWcormaCAdZPLady5
How can I check the input Vcc?
Thanks Mark
https://goo.gl/photos/iWcormaCAdZPLady5
How can I check the input Vcc?
Thanks Mark
Re: Hardware problem
Unfortunately the datasheets are not very clear on what the maximum input voltage is at which the device will still work as advertised. Usually the TO220 versions work up to 25V, while the TO92 versions may start misbehaving at a little over 20V. Yours is a TO220, so that is probably OK.
The easiest access to the input voltage is around D1-D4. Measure between the opposite ends of D1 or D2 and D3 or D4.
The easiest access to the input voltage is around D1-D4. Measure between the opposite ends of D1 or D2 and D3 or D4.
Schelte
-
- Starting Member
- Posts: 14
- Joined: Sun Aug 14, 2016 2:22 pm
Re: Hardware problem
Thanks will try that, meanwhile a replacement part is being shipped hoping it resolves this problem. When it arrives I'll also check to VCC.
Mark
Mark
-
- Starting Member
- Posts: 14
- Joined: Sun Aug 14, 2016 2:22 pm
Re: Hardware problem
Hi
Just received the new L7805CV and before installing I confirmed the VCC (21.1V) which should be OK. Installation of the new L7805CV improved the VCC on pin 15 and 16 of IC2 (5.03V). Next I tested Delay symmetry with loop between boiler en thermo and found this:
OK1A high-to-low: 12us
OK1A low-to-high: 26us
OK1B high-to-low: ### Error
OK1B low-to-high: ### Error
This seems not OK. Can you help me through next logical steps to resolve the none working hardware?
Thanks Mark
Just received the new L7805CV and before installing I confirmed the VCC (21.1V) which should be OK. Installation of the new L7805CV improved the VCC on pin 15 and 16 of IC2 (5.03V). Next I tested Delay symmetry with loop between boiler en thermo and found this:
OK1A high-to-low: 12us
OK1A low-to-high: 26us
OK1B high-to-low: ### Error
OK1B low-to-high: ### Error
This seems not OK. Can you help me through next logical steps to resolve the none working hardware?
Thanks Mark
Re: Hardware problem
Indeed that looks like there is a hardware fault. Check the troubleshooting instructions on how to investigate this.
Schelte
-
- Starting Member
- Posts: 14
- Joined: Sun Aug 14, 2016 2:22 pm
Re: Hardware problem
I checked everything indicate in the trouble shooting and V and A are within range. The last remark was testing #4 which I posted earlier. There is no signal on the Master interface..... Did I miss anything here?
Re: Hardware problem
So you claim that you performed all tests mentioned under "Opentherm interfaces" and they all passed. I'm specifically interested in:
- "If the voltage is correct you can measure the current between the two terminals of X1. It should be between 5mA and 9mA"
- "If you connect pin 3 of the IC1 socket to ground (e.g. pin 5), the current between the two terminals of X1 should be between 17mA and 23mA."
- "Measure the voltage on pin 18 of the IC1 socket with pin 3 left open and again when it is connected to ground. In the former case the voltage should be below 1.25V (it is actually expected to be 0V). In the latter case the voltage must be above 1.25V (and will probably be close to 5V)."
Schelte
-
- Starting Member
- Posts: 14
- Joined: Sun Aug 14, 2016 2:22 pm
Re: Hardware problem
Just checked the mA over the different contacts:
"If the voltage is correct you can measure the current between the two terminals of X1. It should be between 5mA and 9mA"
The current is 6.25mA
"If you connect pin 3 of the IC1 socket to ground (e.g. pin 5), the current between the two terminals of X1 should be between 17mA and 23mA."
The current is 20.2mA
"Measure the voltage on pin 18 of the IC1 socket with pin 3 left open and again when it is connected to ground. In the former case the voltage should be below 1.25V (it is actually expected to be 0V). In the latter case the voltage must be above 1.25V (and will probably be close to 5V)."
in both cases I measure 0V??<--- seems not OK now?? miscounted but after recounting and re-measurement I got 0V and 2.10V between ground and 18..
Thanks for the help so far, what's the next step?
Mark
"If the voltage is correct you can measure the current between the two terminals of X1. It should be between 5mA and 9mA"
The current is 6.25mA
"If you connect pin 3 of the IC1 socket to ground (e.g. pin 5), the current between the two terminals of X1 should be between 17mA and 23mA."
The current is 20.2mA
"Measure the voltage on pin 18 of the IC1 socket with pin 3 left open and again when it is connected to ground. In the former case the voltage should be below 1.25V (it is actually expected to be 0V). In the latter case the voltage must be above 1.25V (and will probably be close to 5V)."
in both cases I measure 0V??<--- seems not OK now?? miscounted but after recounting and re-measurement I got 0V and 2.10V between ground and 18..
Thanks for the help so far, what's the next step?
Mark
-
- Starting Member
- Posts: 14
- Joined: Sun Aug 14, 2016 2:22 pm
Re: Hardware problem
mmmm..
Enter test number: 4
OK1A high-to-low: 10us
OK1A low-to-high: 24us
OK1B high-to-low: ### Error
OK1B low-to-high: ### Error
still not OK?
Enter test number: 4
OK1A high-to-low: 10us
OK1A low-to-high: 24us
OK1B high-to-low: ### Error
OK1B low-to-high: ### Error
still not OK?
Re: Hardware problem
That does look like there is a problem with the opto-coupler. But once again, have you tried if it works? If you don't want to load the gateway firmware, you can try running diagnostics test #2 and #3.
Schelte
-
- Starting Member
- Posts: 14
- Joined: Sun Aug 14, 2016 2:22 pm
Re: Hardware problem
Hi,
just found some time to test the OTGW as you proposed and started test #2 and #3. With both nothing happens (nothing in log or reported on the screen)
Maybe also worthwhile, the thermostat went black... only after connecting the thermostat to the boiler/CV it displayed the temp etc.
Hope this helps to focus on the problem..
Thanks for the support so far.
Mark
just found some time to test the OTGW as you proposed and started test #2 and #3. With both nothing happens (nothing in log or reported on the screen)
Maybe also worthwhile, the thermostat went black... only after connecting the thermostat to the boiler/CV it displayed the temp etc.
Hope this helps to focus on the problem..
Thanks for the support so far.
Mark
Re: Hardware problem
The tests you performed over time produced conflicting results. Possibly there is a loose connection somewhere. Let's first focus on the thermostat. With all components of the OTGW installed but no thermostat or boiler connected, measure the voltage on X1. It should be 24V, or thereabout. Next measure the current. Expect 5-9 mA. Then connect the thermostat and measure the voltage on X1 again. You may see some instability about once per second, but the rest of the time the voltage should have dropped below 8V. If that is the case, run test #2 again. It should report something. If so, proceed from there (connect the boiler and run test #3). If not, check for bad contacts in the slave interface part of the OTGW.
Note: Some thermostats don't show anything until they received a first response. So a black screen does not immediately mean a problem on the thermostat connection.
Note: Some thermostats don't show anything until they received a first response. So a black screen does not immediately mean a problem on the thermostat connection.
Schelte