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fmm
Advanced Member
Username: fmm

Post Number: 231
Registered: 6-2002
Posted on Tuesday, September 30, 2008 - 6:17 pm:   Edit Post

I may be having an issue with the power supply for my Series I.

It's not a rack mount, itís a blue box (except itís black).

Everything worked fine Sunday.
The bass works fine using the ľĒ jack.
So that narrows it down to the 5-pin jack on the bass, the cable, or the power supply.

The cable is an almost new Bayou cable. The leads on my multimeter arenít thin enough to get inside the holes on the female jack, so I canít check for open circuits, but I did check for short circuits and found none. Since the cable is new I think it unlikely thatís the issue.

Iím trying to run down my old cable, but Iíd have to repair it to see if that fixes the issue.

I donít know a good way to test the jack on the bass.

I tried using both output jacks on the power supply with no success. If the power supply is plugged in with no input, thereís more noise than if the 5-pin cable is connected. Iíve opened the case and I donít see any obvious issues. I havenít checked anything with the multimeter with the PS plugged in, because Iím not sure what Iíd be looking for, and Iím not crazy about poking around inside the case while itís plugged in (and yet, I will install new circuit breakers in the house without turning the power off. Go figure.)

Any ideas on how I can further isolate the problem?

Thanks in advance.
lbpesq
Senior Member
Username: lbpesq

Post Number: 3289
Registered: 7-2004
Posted on Wednesday, October 01, 2008 - 7:43 am:   Edit Post

How about sticking one end of a wire into the female holes and touching the multi-meter to the other end of the wire. At least you'll be able to test the cable.

Bill, tgo
fmm
Advanced Member
Username: fmm

Post Number: 232
Registered: 6-2002
Posted on Wednesday, October 01, 2008 - 9:27 am:   Edit Post

I'm not sure why I didn't think of that...
jimmyj
Junior
Username: jimmyj

Post Number: 15
Registered: 8-2008
Posted on Friday, October 03, 2008 - 6:34 pm:   Edit Post

The weakest link on the black or blue box is the actual AC wire both at the molded plug end and the entry point to the little chassis. The conductors break inside the insulation with no obvious sign. Easy to test if the bass has LEDs, if not you will need to listen to the output with the pickup selector on. Power it up, manipulate that wire at the wall plug and at the strain relief and see if the bass loses power.

A new plug is easy but the strain relief grommet is a PITA to repair - but it can be done...
Jimmy J
davehouck
Moderator
Username: davehouck

Post Number: 7114
Registered: 5-2002
Posted on Friday, October 03, 2008 - 7:15 pm:   Edit Post

I'm guessing Jimmy's made that repair a few times.
artswork99
Senior Member
Username: artswork99

Post Number: 488
Registered: 7-2007
Posted on Friday, October 03, 2008 - 7:41 pm:   Edit Post

As Jimmy stated this type of grommet is a PITA (good acronym) but does the job well once snapped in place. When replacing cables I've never figured out a good way to get an electrical cord grommet off without a struggle or damage to the grommet. They do better as a one time use if you can find a replacement to fit and snap in the opening (sure would make it easier to take one off if a replacement were handy).
keith_h
Senior Member
Username: keith_h

Post Number: 1134
Registered: 2-2005
Posted on Saturday, October 04, 2008 - 5:29 am:   Edit Post

Without seeing the bushing I'm guessing that the blue box uses Heyco strain relief bushings. There is actually a special tool used for installing and removing the Heyco strain relief bushings. However it is probably not worth purchasing for one time use. Given this I would take Art's suggestion and buy a new strain relief bushing in the event the old one gets damaged during removal.

Keith
dela217
Senior Member
Username: dela217

Post Number: 912
Registered: 6-2002
Posted on Tuesday, October 07, 2008 - 6:55 pm:   Edit Post

I problem I've found in the past with the blue box is the protective inline diode. If you leave the power supply in a hot car this diode can go bad. I know firsthand on this one!

The diode is before the power transformer in the line cord. You can temporarily bypass the diode to see if it is the problem.
fmm
Advanced Member
Username: fmm

Post Number: 235
Registered: 6-2002
Posted on Wednesday, October 29, 2008 - 5:43 am:   Edit Post

The problem is indeed the power cable at the strain relief. Repairs will commence this weekend.
artswork99
Senior Member
Username: artswork99

Post Number: 497
Registered: 7-2007
Posted on Wednesday, October 29, 2008 - 6:54 am:   Edit Post

That's good to hear and an easy repair.
jimmyj
Junior
Username: jimmyj

Post Number: 16
Registered: 8-2008
Posted on Wednesday, October 29, 2008 - 9:39 am:   Edit Post

Yep, that's good news! Hey Keith, I should really own one of those tools!

It's been a while since I did this but if I remember correctly, I think I shift the transformer off its bolts temporarily to get a bit of working room inside the box. Don't bother if you don't need to. Oh, there is probably some insulation paper in that corner that can be unfolded... Undo the twist connectors at the input of the transformer / diode. I am then ruthless with the pliers squeezing the inside part of the bushing to pop it out.

Once it's out I actually work on the "turn" of the bushing with a file to open it up a bit so I am able to reinstall it - without the special tool thank you very much. Cut off a couple inches of the cord, thread it through the turn leaving enough on the inside to reconnect. Then re-attack the squeezing process from the outside. Be aware that there may be a flat side to the hole which dictates which direction it will fit.

At first it will seem impossible that the cord could make that turn. Now you understand why it fails...

I know, ugly! My technique inevitably damages the bushing because of using the wrong tool... Oh well. At least I didn't suggest pounding it in with the 8" frypan.

Time to replace the molded plug at the other end too. A much simpler job.

Good luck.
Jimmy J
fmm
Advanced Member
Username: fmm

Post Number: 236
Registered: 6-2002
Posted on Saturday, November 08, 2008 - 6:51 pm:   Edit Post

I've replaced the entire power cord, it now works just fine.

Thanks for everyone's help!

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