![]() |
|
|
Thread Tools | Display Modes |
![]() |
#141 |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() I set it to a bit over 50 °C. It heated up and stopped the correct temp with no issues. What should I do at this point? I m tempted to ignore the abnormaly (if it is abnormal) low current. I don't know what to put in place of the blown resistance.
One thing I noticed is the heatsink of the triac gets very hot. Too hot to touch, but suppose that's normal. ![]() |
![]() |
![]() |
![]() |
#142 |
Badcaps Veteran
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 3,233
|
![]() cant see the pic very good . are you sure its not saying 100 milliamps ?
|
![]() |
![]() |
![]() |
#143 |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() |
![]() |
![]() |
![]() |
#144 |
Solder Sloth
Join Date: Nov 2012
City & State: CO
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 7,163
|
![]() The LM324 sitting on the 12/20V wire has a quiescent supply current of a milliamp by itself so you're seeing something less than 1mA (= 1000µA), the op amp is not getting power. This says nothing about all the other stuff on that line that also needs power.
|
![]() |
![]() |
![]() |
#145 |
Badcaps Veteran
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 3,233
|
![]() more than a resistor blown then ..maybe the fuse in the meter or leads in wrong holes or something silly like that . or meter is on dc amps ..
|
![]() |
![]() |
![]() |
#146 | ||
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() Quote:
Quote:
If this reading is correct, then going back to my previous calculations to drop 4v across a resistor, I would need 4/0.075 or about 53 Ohms. Should I try to see if there is something else fried or is 75 mA plausible? Last edited by vrasp; 06-20-2021 at 07:05 PM.. |
||
![]() |
![]() |
![]() |
#147 |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() I soldered a 50 ohm resistor. The voltage drop across the resistor is 2.9v. The current going through is therefore about 60 mA. I havent noticed anything wrong with the waterbath. It seems to be working fine.
I will put everything back together tomorrow (carefully, unlike previous times), run it for a few hours, and see how it goes. Thanks a lot for your help guys! |
![]() |
![]() |
![]() |
#148 |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() Today I put everything back together. I used the cooling option to bring the temp down to 5 degrees Celsius then heated up the water to 80 degrees celcius. It ran for over an hour with no issues. I think it s ready to go back to the lab.
Now I ve been asked to look at a laboratory grade oven. Apparently it s also an electrical issue. I ll start a new thread if I need some help (which will likely be the case). I ve already said this but I m really grateful for your help. I have very little experience fixing electronics so this was new to me. I learned a lot! Thank you for your patience and guidance. ![]() Last edited by vrasp; 06-22-2021 at 06:56 PM.. |
![]() |
![]() |
![]() |
#149 |
Badcaps Veteran
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 3,233
|
![]() well done to all concerned .
|
![]() |
![]() |
![]() |
#150 |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() Hey guys, I am back.. with an issue.
What happened: The waterbath worked well for 2 days. I left it at 80 °C most of the day yesterday. As I was about to turn it off, I decided to press the cooling button. I had done that before without issues. This time, the display stopped working when I pressed it. When this button is activated, the cooling system (compressor amongst other things) is activated and creates some vibrations. No smoke or other relevant observations. The details: The waterbath still works. I can change the temperature. The water heats up. I can cool it using the cooling option. The LED on the display board works too (the yellow LED that indicates whether it is heating or reached chosen temperature). What does not work is the display. What I have done: - I measured the current where I had put a 50-ohm resistor (before the bridge rectifier of the green/blue board). The last time, when it was working fine, I was getting around 75 mA. This time I m getting around 50 mA. - I measured the voltages on the display board. It's getting 5-6v. - I checked for a bad connection. I don't think there is any. Pocking stuff around did not make the display turn back on. There is continuity in all connections between the green/blue board and the display board. I don't fully understand how the LM324DP and ICL7107SCPL work, but I think that LM324DP isn't related to the display. Since everything works fine except the display, I am tempted to say that it has to do with the ICL7107. Again, that's based on my basic understanding of the circuit. Hopefully someone is able to give me a hint of what I can check with this information. How can I test ICL7107? What would you do at this point? This is the most detailed schematic of the circuit (last page). http://www.hvg-verwertung.de/ebay/do...da/RMS6_20.pdf Thank you! Last edited by vrasp; 06-24-2021 at 10:14 PM.. |
![]() |
![]() |
![]() |
#151 |
Badcaps Veteran
Join Date: Jul 2011
City & State: Some times Sunny Jacksonville FL
My Country: USA
Line Voltage: 120 Volts 60 HZ
I'm a: Knowledge Seeker
Posts: 3,565
|
![]() The ICL7107SCPL is nothing more that a voltage meter module you need to look at the data sheet for voltage in for the meter module to work and make sure you have voltage at these points that pins V+ which pin1 and V- pin26 ground pin is 21
Here is the data sheet website link https://media.digikey.com/pdf/Data%2...007,%2007S.pdf You have to have a 5+ ground 5- for a power supply unless this unit has a negative power supply regulator ic chip I hope this helps you
__________________
9 PC LCD Monitor 6 LCD Flat Screen TV 30 Desk Top Switching Power Supply 10 Battery Charger Switching Power Supply for Power Tool 6 18v Lithium Battery Power Boards for Tool Battery Packs 1 XBox 360 Switching Power Supply and M Board 25 Servo Drives 220/460 3 Phase 6 De-soldering Station Switching Power Supply 1 Power Supply 1 Dell Mother Board 15 Computer Power Supply 1 HP Printer Supply & Control Board * lighting finished it * These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10% 1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later ) 2 Hem Saw Computer Stack Board All of these had ![]() All of the mosfet that are taken out by bad caps ![]() Last edited by sam_sam_sam; 06-25-2021 at 09:14 PM.. |
![]() |
![]() |
![]() |
#152 | |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() Quote:
This is the component. It says 825 then A below it. I think something is shorted to ground somewhere on this line. |
|
![]() |
![]() |
![]() |
#153 |
Solder Sloth
Join Date: Nov 2012
City & State: CO
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 7,163
|
![]() If you inject 5V and it turns on, and it's not drawing a lot of power, this line doesn't sound shorted, it sounds open, and isn't that connector a previous point of weakness?
|
![]() |
![]() |
![]() |
#154 |
Badcaps Veteran
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 3,233
|
![]() component looks like a 6.2v zener 500mw
|
![]() |
![]() |
![]() |
#155 |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() I think the line has continuity though. I have to double check.
I injected 5v by using one if the LED power lines and connecting it directly to v+ of ICL. The display turns on, its dim, but it turns on. I dont know how much power it draws. I guess I could put my ammeter in there too. My assumption was that the component I showed in the previous picture was broken. I put a wire instead to see what would happen but still 0v. However when nothing is connected, one pin has 6v. Wouldnt that mean that something is shirrer to ground? I was going to check the other components on this line. This is the line. The black lines mean there is a component on the other side. Last edited by vrasp; 06-26-2021 at 05:02 AM.. |
![]() |
![]() |
![]() |
#156 |
Badcaps Veteran
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 3,233
|
![]() never just bridge components if you don't know what they are .
that zener is there for good reason . and most likely should read 6.2v right across it . |
![]() |
![]() |
![]() |
#157 | |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() Quote:
Yes, it read 6.2v on one pin but not on its pin going to the display. Do you think the zener is the issue? |
|
![]() |
![]() |
![]() |
#158 |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() My next step is to double check for continuity and if there is continuity, check each component on this line to make sure it s doing its job.
|
![]() |
![]() |
![]() |
#159 |
Badcaps Veteran
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 3,233
|
![]() zener appears fine ,
bridging resistors can also make bad things happen .. in fact bridging anything can ..just don't do it . test the suspects properly . |
![]() |
![]() |
![]() |
#160 |
Senior Member
Join Date: Nov 2019
City & State: Toronto
My Country: Canada
I'm a: Knowledge Seeker
Posts: 174
|
![]() There is continuity from the output of the zener all the way to the v+ of ICL. The input of the zener has 6.2v and 0v on the output
Last edited by vrasp; 06-26-2021 at 08:05 AM.. |
![]() |
![]() |
![]() |
Thread Tools | |
Display Modes | |
|
|