wrong output voltages Generac 7550EXL

Portable standby generator troubleshooting and repair questions. (Gasoline, diesel, propane, natural gas)
Jimape123
New Member
New Member
Posts: 5
Joined: Thu Jan 14, 2021 7:53 pm

It may not be perfect , even if off by a hundred look at the voltages, one is at low idle one is at running speed.
Unit bought by me new , might have 12 hours on it tops.... Not even broke in, same oil never changed, put in a new regulator no change. Smokes appliances . literally.
What's my next step? Worked fine then lights got bright fridge smells funny, capacitors in powered subwoofer ( on standby mode) on fire smoke Coming from cabinet. Put the meter on and 160 volts +. Can't find help anywhere for this.
Attachments
20210114_172809.jpg
20210114_172809.jpg (91.78 KiB) Viewed 2339 times
20210114_151002.jpg
20210114_151002.jpg (55.51 KiB) Viewed 2339 times
20210114_151007.jpg
20210114_151007.jpg (54.31 KiB) Viewed 2339 times
Jimape123
New Member
New Member
Posts: 5
Joined: Thu Jan 14, 2021 7:53 pm

What next.
Jimape123
New Member
New Member
Posts: 5
Joined: Thu Jan 14, 2021 7:53 pm

Assuming both meters are within specs and a new regulator does not change anything, what next? That one pic is of a control board behind the outlets.
Chris
Site Admin
Site Admin
Posts: 4826
Joined: Sat Aug 04, 2018 8:46 pm
Location: Clawson, MI
Contact:

I would shoot BassGuitarist a PM. He knows these units inside and out and can repair the PCB's on them. He's really the best source of knowledge on these older portable units! :cool:
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
Bassguitarist1985
Contributor
Contributor
Posts: 53
Joined: Wed Jan 23, 2019 12:37 am

Jimape123 wrote:
Fri Jan 15, 2021 7:59 pm
Assuming both meters are within specs and a new regulator does not change anything, what next? That one pic is of a control board behind the outlets.
Chris wrote:
Mon Jan 18, 2021 12:00 pm
I would shoot BassGuitarist a PM. He knows these units inside and out and can repair the PCB's on them. He's really the best source of knowledge on these older portable units! :cool:
The next step is to rebuild the board, replace the components that are bad. What revision do you have? should say in the bottom right hand corner. Boards are NLA, but can be fixed, even the SMD style one. Electronic components themselves are not expensive, its simply the time involved to properly desolder, replace, then test on the jig, and also in my 7000EXL.

Your generator will keep smoking appliances with voltages in the 160-170VAC range. The system control board acts as a negative feedback circuit, it sends a signal to the voltage regulator to maintain a set voltage. If it does not see that signal, it outputs full power. Common circuit design but a dangerous one because of the circuit fails then you blow anything connected to it unless you got a surge protector. Conventional knowledge would suggest a positive feedback loop circuit where if the SCB fails the voltage regulator shuts down, but if that circuit fails, usually in the closed/shorted condition, the voltage goes high anyway. Thus why the negative feedback snubber circuit was used as the lesser of the two evils.

Anyways, will PM you on the rebuiild and let me know if it works for you.

Bass
Jimape123
New Member
New Member
Posts: 5
Joined: Thu Jan 14, 2021 7:53 pm

Pics
Attachments
20210120_152350(1).jpg
20210120_152350(1).jpg (73.09 KiB) Viewed 2302 times
20210120_152350(1)(1).jpg
20210120_152350(1)(1).jpg (119.05 KiB) Viewed 2302 times
Bassguitarist1985
Contributor
Contributor
Posts: 53
Joined: Wed Jan 23, 2019 12:37 am

PM Sent
gener14701
New Member
New Member
Posts: 1
Joined: Tue Jul 13, 2021 9:30 pm

Hi Bassguitarist1985 - I have a similar issue with overvoltage. I was trying to fine-tune the output voltage and I believe I have damaged the blue potentiometer that you can access through the side panel.

Can you PM me about this?
Bassguitarist1985
Contributor
Contributor
Posts: 53
Joined: Wed Jan 23, 2019 12:37 am

PM sent!
BillL
New Member
New Member
Posts: 1
Joined: Tue Oct 12, 2021 11:48 pm

Hello
My 6500XL is putting out 155 volts after getting accidentally sprayed with the hose. Replaced the voltage regulator board and the voltage trim pot on the main control PCB. Still no improvement. Any advice on where to buy a control PCB or other components to replace on the board?
Bill
Post Reply