Dewalt 788 Printed Circuit Board Schematic - Scroll Saw Woodworking & Crafts Message Board

Don McLeod · 01-05-2009, 01:09 AM

I have done a search for a schematic for the PC board for the 788 and have been unable to locate one. Do you know where I can find one?
I believe that I have pinpointed the problem with the Dewalt 788 that is blowing fuses.
I removed the motor, switch and pot from the circuit and when I plugged in the saw, the fuse lasted long enough to give a reading on my meter of 50volts DC at the motor connections on the board before it blew. I do not see a trace that is burn't or broken, nor do I see any indication of a component that looks burn't or broken.
If you have an idea on how to test it further or know what component could be shorting please let me know.

Thanks
Don McLeod

Powakee · 01-05-2009, 03:50 AM

Don, Have you tried Black & Decker's web site. I am under the belief that they bought out DeWalt on this tool, or maybe they actually bought out DeWalt. I haven't looked but I do recall having looked for a DeWalt replacement parts list once and found the list. If you don't have any luck IM me and I'll take a look again.

John

NMScroller · 01-05-2009, 12:02 PM

I hope B&D decides not to tinker with the design on that top selling saw.

Mick Walker · 01-05-2009, 06:19 PM

From what I understand, Black & Decker bought out Porter Cable, DeWalt and Delta. That is why they stopped making the Delta scroll saws.

lonepine · 01-05-2009, 08:08 PM

Don; Iv'e tried to find the schematic also...apparently there is not one.I personally asked the bench servive person at the repair facility and got a you want a what?
The correct voltage output is 50-100 volts DC. there is a rectifier or scr (changes current to one way)that if it shorts,it will blow the fuse...
Hope this helps...
I do have a spare that I replaced, i'll try to check it closer and see which I think it is.
Rob

Don McLeod · 01-16-2009, 12:09 AM

I haven't found a circuit board schematic and if one exists on the net I'm unable to find it. It s not available from Dewalt. From one of the posters on this forum I found out that B&D have a limit on what they charge to repair this saw, so that is the way I'll go. If all they find wrong with the saw is the board, it should be about $150.00 CDN

I have asked that the board be returned to me when I pick up the saw and I'll try and get a schematic drawn off .

Thanks for your help.

Don

JMay · 01-16-2009, 01:40 AM

Quote:

Originally Posted by Don McLeod

I haven't found a circuit board schematic and if one exists on the net I'm unable to find it. It s not available from Dewalt. From one of the posters on this forum I found out that B&D have a limit on what they charge to repair this saw, so that is the way I'll go. If all they find wrong with the saw is the board, it should be about $150.00 CDN

I have asked that the board be returned to me when I pick up the saw and I'll try and get a schematic drawn off .

Thanks for your help.

Don

Gotta love the guarantee repair charge they offer. I had a Dewalt cordless drill and impact gun fixed and they had to replace everything but the cases so it was the maximum charge but still a lot cheaper than buying new.

axial2008 · 01-16-2009, 12:56 PM

My two cents worth. I had the EXACT same issue with my CAN made 788. While trying to locate the problem, I ended up frying the motor. Ended up needing motor and CB, so I took everything apart as spare. Luckily this was a garage sale find for $100, so it wasn't bad, and my other 788 is perfect. I agree with Josh, the guarantee repair policy is a good one when its major like this.
Axial

marshall · 01-16-2009, 01:11 PM

Don I wish I could help

, but I'll be watching for your findings of you problems . I also have the 788 and no problems so far , let us all know what comes of this . Good Luck .........Marshall

Wood Dog · 01-16-2009, 02:16 PM

Don..another member was looking for a schematic a while back, I don't know if this thread will help you, or maybe you could pm markdavd for more info
anyone have pic of inside wiring dw788

01-05-2009, 01:09 AM	#1
Don McLeod Junior Member Join Date: Oct 2008 Posts: 5	Dewalt 788 Printed Circuit Board Schematic I have done a search for a schematic for the PC board for the 788 and have been unable to locate one. Do you know where I can find one? I believe that I have pinpointed the problem with the Dewalt 788 that is blowing fuses. I removed the motor, switch and pot from the circuit and when I plugged in the saw, the fuse lasted long enough to give a reading on my meter of 50volts DC at the motor connections on the board before it blew. I do not see a trace that is burn't or broken, nor do I see any indication of a component that looks burn't or broken. If you have an idea on how to test it further or know what component could be shorting please let me know. Thanks Don McLeod

01-05-2009, 03:50 AM	#2
Powakee Senior Member Join Date: Mar 2005 Location: Northern Edge of the Great Sonoran Desert Posts: 531	Don, Have you tried Black & Decker's web site. I am under the belief that they bought out DeWalt on this tool, or maybe they actually bought out DeWalt. I haven't looked but I do recall having looked for a DeWalt replacement parts list once and found the list. If you don't have any luck IM me and I'll take a look again. John __________________ I've Still Got A Lot More To Learn About Leaving Battlegrounds Alone ~~ Molly Venter

01-05-2009, 12:02 PM	#3
NMScroller Senior Member Join Date: May 2007 Location: Columbia, SC Posts: 321	I hope B&D decides not to tinker with the design on that top selling saw. __________________ ---Support bacteria - they're the only culture some people have.

01-05-2009, 06:19 PM	#4
Mick Walker Senior Member Join Date: Jan 2005 Location: Janesville, WI Posts: 1,493	From what I understand, Black & Decker bought out Porter Cable, DeWalt and Delta. That is why they stopped making the Delta scroll saws. __________________ Mick, - Delta P-20 The future ain't what it used to be.

01-05-2009, 08:08 PM	#5
lonepine Senior Member Join Date: Aug 2004 Location: Western,Penn. Posts: 164	Don; Iv'e tried to find the schematic also...apparently there is not one.I personally asked the bench servive person at the repair facility and got a you want a what? The correct voltage output is 50-100 volts DC. there is a rectifier or scr (changes current to one way)that if it shorts,it will blow the fuse... Hope this helps... I do have a spare that I replaced, i'll try to check it closer and see which I think it is. Rob __________________ The provide-ance of God is my inheritance

01-16-2009, 12:09 AM	#6
Don McLeod Junior Member Join Date: Oct 2008 Posts: 5	Schematic I haven't found a circuit board schematic and if one exists on the net I'm unable to find it. It s not available from Dewalt. From one of the posters on this forum I found out that B&D have a limit on what they charge to repair this saw, so that is the way I'll go. If all they find wrong with the saw is the board, it should be about $150.00 CDN I have asked that the board be returned to me when I pick up the saw and I'll try and get a schematic drawn off . Thanks for your help. Don

01-16-2009, 12:56 PM	#8
axial2008 Junior Member Join Date: Aug 2008 Location: Atlanta, GA Posts: 10	My two cents worth. I had the EXACT same issue with my CAN made 788. While trying to locate the problem, I ended up frying the motor. Ended up needing motor and CB, so I took everything apart as spare. Luckily this was a garage sale find for $100, so it wasn't bad, and my other 788 is perfect. I agree with Josh, the guarantee repair policy is a good one when its major like this. Axial

01-16-2009, 01:11 PM	#9
marshall Just love Being Here Join Date: May 2008 Location: Jonesboro Arkansas { USA } Posts: 2,664	Don I wish I could help , but I'll be watching for your findings of you problems . I also have the 788 and no problems so far , let us all know what comes of this . Good Luck .........Marshall __________________ Usually busier than a cat in a sandbox !!!!!!!!!!! { Dewalt 788 only }

01-16-2009, 02:16 PM	#10
Wood Dog Senior member--Absolutely Join Date: Jul 2007 Location: MA USA Posts: 3,934	Don..another member was looking for a schematic a while back, I don't know if this thread will help you, or maybe you could pm markdavd for more info anyone have pic of inside wiring dw788 __________________ WD

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