Re: Onkyo TX-NR708 standby light
I say that because you momentarily have the juice to power the LED, but then you don't.
Voltage will always push a current via the 'path of least resistance' to ground, so perhaps something is a quicker/shorter path than your standby LED? Something quasi-shorting?
The voltage must be being diverted somewhere....
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Re: Onkyo TX-NR708 standby light
Just a quick one, but considering that the unit is essentially dead, it wouldn't hurt to verify the power supply. You might wanna check everything including the large filter caps.
Something appears to be pulling the standby voltage down on start-up, so maybe see what else is in the stand-by circuit?
Even without the stby led, have you 'tried' to do the reset?
If you can share the service manual then I'm sure you'll get more help in finding the solution.Last edited by Crystaleyes; 10-18-2023, 10:38 AM.
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Re: Repairing a snapped pcb
Some excellent tips and suggestions, most of which I can see being extremely useful, so nice one, for all the input.
Haven't had a free moment to try any of these out yet but gonna get on it in the coming days.
Wish me luck!
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Re: Repairing a snapped pcb
Some excellent suggestions, so thank you sincerely.
One observation is that some of the broken traces are really fine, therefore it is easier to run longer lines and those would need some form of insulation.
As for using solid copper.. I like that, and have lot's of that here.
I-ll keep you all updated as I do this work
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Re: Repairing a snapped pcb
This is also what had crossed my mind.
There are areas with just resistors or links (which could easily be replaced with longer legs), where another piece of board could be added and the holes re-drilled with a Dremel....
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Re: Repairing a snapped pcb
Do you reckon I could get away with enameled speaker wire on the thinner traces?...
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Re: Repairing a snapped pcb
Thanks for the suggestions...
To be honest, board strength has been my main concern, although after soldering the thicker traces, the board pictured is already fairly rigid again.
I should finally be back in England next month, earning real wages, so I was thinking of ringing up Allen & Heath and seeing if they had any old 'blank' boards laying around that they would sell?
I need both the boards with the LED power bars.
And seeing how I essentially got the mixer for free, it...
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Re: Repairing a snapped pcb
Sounds interesting.
Didn't know that it existed
Just looked it up, wicked stuff. What a great idea!Last edited by Crystaleyes; 10-15-2023, 03:51 PM.
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Repairing a snapped pcb
Hi all.
Recently picked a very cheap (20 Euros) Allen and Heath XONE 62 DJ mixer, which had clearly been dropped and upon opening up, has two snapped pcb's.
Other than bridging each trace, does anyone have any other suggestions or ideas as to how to resolve these?
There are probably twenty broken traces on each board.
The photos are of the board I glued with No More Nails (just to get things started).
I was thinking of using enameled speaker wire......
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Re: Onkyo TX-NR708 standby light
This series of home theater systems is plagued by various issues.
Although I've not worked on many, I have opened a few.
I scrapped one for parts after the problem was a microproscessor which after importing from China, wouldn't have been cost effective and with the output transistors are expensive over here, time had run out for that particular unit.
I've seen the 'stuck in standby' problem resolved tthrough doing a reset by pressing certain butons on start-up, but you will have to research as to which buttons...Last edited by Crystaleyes; 10-14-2023, 04:17 AM.
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Re: Calculating resistor values in parallel with Caps
In the end I found a single 75R (which measured 79Ω) 1W resistor in my supplies and installed that.
So, I reckon this thread is closed.
I needed to work out what the burnt resistor value had been and am 90+% sure that it was +/- 82Ω.
Thanks for all the input as I have learned a valuable lesson here.
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Re: Calculating resistor values in parallel with Caps
So...
Came across an article which suggested removing the burnt coating from the resistor in order to see how many spiral stripes there were.
The less stripes, the lower the resistance value. Makes sense...
As can be seen in photo #1, the original resistor appears to have roughly two stripes, which (according to the article) would indicate a value of between 10 to 100Ω.
Measuring the burnt resistor however reads just over 150Ω.
Considering that resistances...Last edited by Crystaleyes; 10-08-2023, 10:36 AM.
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Re: Electrolux ERG22 vacuum cleaner pcb fault
A final word and this thread is closed...
The second unit only needed one charge in order to come back to life.
As for the original, it is now returned to the owner, who asked what the problem had been?
Not wishing to 'let a good crisis go to waste' I told him that it was his good fortune that I am somewhat of an electronics repair genius, and that the problem had been a design fault on the part of the Electrolux engineers.
I told him that one of the trans-flux, variable wing dipacitors...
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Re: Electrolux ERG22 vacuum cleaner pcb fault
It lives!!
I had charged the new battery pack and it still didn't work, so bearing in mind what you said, with the motor disconnected and the board on the bench with only the batteries, I just kept charging it until the charge led went off, then unplugging the charger for a few hours.
Somewhere around the fifth charging cycle, it finally started putting the battery voltage out to the motor terminals.
It is now fully reassembled and working fine. Have run it through a couple...
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Re: Electrolux ERG22 vacuum cleaner pcb fault
Yeah, all over it...
I hadn't thought of that
Actually, I didn't try connecting the charger perhaps as the battery pack was showing +/-12v when the 'official' motor voltage is 10.8v.
Probably have to do all this tomorrow as have been having 12 hour work sessions recently, but thanks for the suggestions. Most appreciated.
I've changed many battery sets in the past but never had this happen. Maybe it is something as basic as it needing a charge?...
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Re: Electrolux ERG22 vacuum cleaner pcb fault
Hi mate.
There's not really any flux on the board. All that residue is from where I've been scratching off the varnish in order to read the component numbers.
Didn't get a chance to do anything last night but will have another go after work today.
I had thought about jumping the power... I'll give that a go. Cheers!...
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Re: Electrolux ERG22 vacuum cleaner pcb fault
Thanks to R_J for identifying the NG1N as a PNP although that hasn't helped me understand any more how the circuit should be working.
The circuit has a three pin HT7533, 3.3v voltage regulator which has zero volts on the 'voltage in' pin.
Following the circuit back it arrives at the emitter of the above mentioned PNP. I would have expected an NPN on that circuit.
I've never fully understood PNP transistors but had always been under the impression that the base must be negative to the...
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