Author Topic: Series Power Supply Issue (?) (Read 274 times)

fmm · « **on:** September 30, 2008, 06:17:25 PM »

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

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

Everything worked fine Sunday.
The bass works fine using the ?? 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 aren?t thin enough to get inside the holes on the female jack, so I can?t check for open circuits, but I did check for short circuits and found none. Since the cable is new I think it unlikely that?s the issue.

I?m trying to run down my old cable, but I?d have to repair it to see if that fixes the issue.

I don?t 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, there?s more noise than if the 5-pin cable is connected. I?ve opened the case and I don?t see any obvious issues. I haven?t checked anything with the multimeter with the PS plugged in, because I?m not sure what I?d be looking for, and I?m not crazy about poking around inside the case while it?s 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 · « **Reply #1 on:** October 01, 2008, 07:43:54 AM »

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 · « **Reply #2 on:** October 01, 2008, 09:27:18 AM »

I'm not sure why I didn't think of that...

JimmyJ · « **Reply #3 on:** October 03, 2008, 06:34:44 PM »

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

David Houck · « **Reply #4 on:** October 03, 2008, 07:15:56 PM »

I'm guessing Jimmy's made that repair a few times.

artswork99 · « **Reply #5 on:** October 03, 2008, 07:41:37 PM »

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 · « **Reply #6 on:** October 04, 2008, 05:29:14 AM »

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 · « **Reply #7 on:** October 07, 2008, 06:55:50 PM »

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 · « **Reply #8 on:** October 29, 2008, 06:43:10 AM »

The problem is indeed the power cable at the strain relief. Repairs will commence this weekend.

artswork99 · « **Reply #9 on:** October 29, 2008, 07:54:01 AM »

That's good to hear and an easy repair.

JimmyJ · « **Reply #10 on:** October 29, 2008, 10:39:13 AM »

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 · « **Reply #11 on:** November 08, 2008, 06:51:40 PM »

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

Thanks for everyone's help!