Dewalt 788 questions

[Grumpy Old Bear]

I have been having trouble with my 788. I was told the speed control 'pot' was fine and did not need to be replaced. when I turn the speed up past 2½ or 3 the saw makes all kinds of racket. My main question is: When bearing go bad do they rattle and make noise at any speed or do they only react at certain speeds?  The other questions is: in order to remove the circuit board from this saw, are all the wires just like plug and play, or is there de-soldering to be done? I do not have th saw with right now so I can't open it up to look, and the exploded view doesn't help much.

I appreciate any and all help I can get.

Jim

[fredfret]

Bearings can "work" well at one speed and not at another. Usually the higher the speed the more problems. I believe the wires are all plug in/on. Gwennet woodworkers has a fine video of the bearing replacement procedure but I dont have the exact title for it. You Tube has it. I have not had a need to replace my bearings in the 788 and may never as I use the Hawk 99.98% of the time.

Fredfret

Wichita, Ks

[GrampaJim]

I agree with Fredfret.  Watch the videos, there are four of them. 

I just replaced all the bearings and bushings on my Dewalt.  Compared to what the YouTube videos show as "bad" all the old ones in mine looked pretty good to me.  Since I already had the new parts in front of me, I put them in anyway.  Before the saw was really loud above speed 5, now it just purrs.  If you are careful, you will not have to remove or touch the circuit board - just make sure you unplug the machine.  I was more than a little nervous about tacking the bearings but its not really that bad. 

[Ctutor]

Had a similar problem. Found that the bolt holding the arm at the back had worked loose. One of the common problems is the adjustment at the front of the speed controller. There is a video by the Gwanette woodturners that goes through the disassembly of the 788 and various fixings. If you can not find it let me know and I'll dig it up. Bearings may be a problem but probably not. How old is the unit? The disassembly looked to be formidable but was not. Very straight forward and it took less than an hour to take it apart and put it back together. There is another site ( I think it starts with a person's name) that has all kinds of fixes for the 788 various problems and adjustments.Again if you can't find it let me know and I'll try to dig up the links.

[hawkeye10]

I bought a DW788 new and the bearings were bad or at least there was no grease in them. I took it back and bought a EX16 and have been happy. I have said this several times that if I had to buy a DW788 I would tear it down and replace the bearings. There is a lot of post on here about people having trouble with their 788's. Okay I will admit that there are those that don't have trouble "YET".  I wonder if there is a repair video on an Excalibur scroll saw.  

[Bill WIlson]

2 hours ago, Ctutor said:

Had a similar problem. Found that the bolt holding the arm at the back had worked loose. One of the common problems is the adjustment at the front of the speed controller. There is a video by the Gwanette woodturners that goes through the disassembly of the 788 and various fixings. If you can not find it let me know and I'll dig it up. Bearings may be a problem but probably not. How old is the unit? The disassembly looked to be formidable but was not. Very straight forward and it took less than an hour to take it apart and put it back together. There is another site ( I think it starts with a person's name) that has all kinds of fixes for the 788 various problems and adjustments.Again if you can't find it let me know and I'll try to dig up the links.

Good point!  I think it's important to emphasize that there are other issues, besides bearings that could contribute to noise.  The drive linkage has some connecting points where bolts can and do work loose and may also cause knocking. 

Perhaps it was Rick Hutcheson's site that you are thinking of?

 

http://www.scrollsaws.com/

 

 

 

 

Edited June 1, 2017 by Bill WIlson

[WayneMahler]

All good information and ideas above. The video that was mentioned is a 4 part series. Here is the link for the 1st part. You should be able to follow the rest from there.

 

If needed I can supply the other links also.

Best of luck figuring your issue out.

 

[Grumpy Old Bear]

I want to thank everyone for their advice and assistance. I know I have gotten some of this info in an earlier post, but this reinforces all of that knowledge. I will be spending my weekend either at the library watching videos or in the shop looking in my saw.

Thanks again everybody.

[Sparkey]

It could also be as easy as a loose nut or bolt someplace. I would open it up and check them first.

[poupster2]

On 6/1/2017 at 0:57 PM, WayneMahler said:

All good information and ideas above. The video that was mentioned is a 4 part series. Here is the link for the 1st part. You should be able to follow the rest from there.

 

If needed I can supply the other links also.

Best of luck figuring your issue out.

 

Thank you Wayne, awesome video!  Now to get the parts list !

[amazingkevin]

On 6/1/2017 at 7:38 AM, Stupid Donkey said:

I have been having trouble with my 788. I was told the speed control 'pot' was fine and did not need to be replaced. when I turn the speed up past 2½ or 3 the saw makes all kinds of racket. My main question is: When bearing go bad do they rattle and make noise at any speed or do they only react at certain speeds?  The other questions is: in order to remove the circuit board from this saw, are all the wires just like plug and play, or is there de-soldering to be done? I do not have th saw with right now so I can't open it up to look, and the exploded view doesn't help much.

I appreciate any and all help I can get.

Jim

For the most part they un plug I dearly love them but i don't like working on watches.