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Topic: Molex connectors problem help? |
Jerry Roller
From:
Van Buren, Arkansas USA
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Posted 15 Oct 2009 5:56 pm |
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I have a Session 400 with hum isolated to he molex connectors, the on on the power supply from the preamp seems to be to worse one. I have tighted it up, cleaned and the hum still changes when I barely move the wires going into the connector. Is it ever advisable to remove a molex connector and wire it in direct. I need advise from someone who has real experience with this, please.
Thanks,
Jerry |
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Jim Palenscar
From:
Oceanside, Calif, USA
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Posted 15 Oct 2009 6:01 pm
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| There are times when one of the base connectors gets loose on the circuit board and needs re-soldering. This is especially common in the reverb connectors. |
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Jerry Roller
From:
Van Buren, Arkansas USA
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Posted 16 Oct 2009 8:58 am
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Thanks Jim. I will pull the boards back out and check those pins.
Jerry |
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Jack Stoner
From:
Kansas City, MO
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Posted 16 Oct 2009 10:13 am
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Sometimes the Molex pins on the circuit board will develop "hairline" cracks that you can't see. The only way to check is for continuity with an ohmmeter. Or just resolder the pin to the circuit board (and hope that fixes it).
I had one on a Nashville 400 reverb connection that drove me crazy. It had intermittent hum when it was new (and this one was a new direct from Peavey not one that was sitting in a music store), I worked on it and at the time couldn't find anything. The amp blew up while in warranty and it was sent to Peavey and after repair the Reverb still had a hum in it and the chassis was sent back to Peavey and they couldn't find any problems. About a year after that I finally got back into it and located the "hairline" crack and fixed it. |
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David Mullis
From:
Rock Hill, SC
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Posted 17 Oct 2009 10:00 am
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So other than it making it more difficult for future maintenance etc, are there any reasons NOT to do away with the molex connectors and just solder the wires directly to the board? I thought about doing this recently as it's kind of a pain to pull a chassis and reseat/clean molex connectors if you notice a problem at a gig. I think it would make the Session 400 more bullet proof but, I'd like to hear from somebody that knows more than I do.  |
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Jim Palenscar
From:
Oceanside, Calif, USA
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Posted 17 Oct 2009 10:03 am
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| Just as soon as you solder them directly something will come up that you'd wish you hadn't- it seems like it always happens this way~~and if you don't-it will last forever- C'est la vie |
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Scott Appleton
From:
Ashland, Oregon
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Posted 17 Oct 2009 12:30 pm To molex or not to molex
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the great thing about molex is it can be repaired. As long as you know from the
start that it can be a problem then fixing them is not. The big deal for most people is the cost of the AMP Pin tool .. around 240$ .. The wiring is not soldered
on those pins its crimped .. which does corrode after some time. The pins on the
circuit board are a different problem.. One way to improve repairability is to solder a cable directly to the board and then set a pair of Molex connectors mid
cable so the reverb unit can be unplugged and repaired outside of the chassis.
If the cable goes to the reverb tank with RCA connectors then soldering to the
CB should not create any problems if the tank needs replacing. Other inter
circuit board molex connectors and cables offer challenges which a good technician can work around but again they usually just repair the problem rather than hard wire in that case. |
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David Mullis
From:
Rock Hill, SC
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Posted 17 Oct 2009 2:17 pm
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| Ok, so, knowing that the pins are crimped onto the wires, would there be any benefit to soldering new pins to the cables and reusing the molex connector (providing they're ok)? The way I see it, this would make for fewer mechanical connections and less possible points of failure. The pin extraction tools are pretty cheap! |
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Scott Appleton
From:
Ashland, Oregon
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Posted 17 Oct 2009 5:04 pm Molex pins
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Those Pins don't take solder very well .. I have tied it and caused more hassle
than just using a cheap crimper.. You can squeeze crimp them it just is not
as secure as the proper compression tool. |
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Jack Stoner
From:
Kansas City, MO
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Posted 18 Oct 2009 2:08 am
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The crimp part rarely causes a problem. If it's OK when initially crimped it will remain OK. I have a $20 (US Made) crimp tool that I bought years ago that I use.
The biggest problem with the Molex connectors is the application that Peavey used them for. They were designed for "power" not low level "signal" and are/were a cheap (cost) connector. |
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Chuck Snider R.I.P.
From:
West Virginia, USA - Morgantown, WV
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Posted 18 Oct 2009 8:02 am
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One thing that will help minimize, if not eliminate, corrosion at the connector is to separate the connector and apply a little dab of dielectric grease to each connector piece. Use enough to thoroughly encapsule the connector, you're basically wanting to keep the metal parts from contacting the air resulting in corrosion/oxidation. It is the same stuff used inside current day spark plug connectors on cars, and you can get a small packet at the checkout of you local auto parts store. If I recall the price is around 1 dollar, if not less, and it will be enough to last you a lifetime.
-Chuck
_________________
GFI U-12 Ultra Keyless, Carter Black U-12, both with Alumitones, and a sweet '70 Sho-Bud Permanent D-10, NV400 in Rick Johnson cabs, NV112, '73 Vibrosonic in Rick Johnson cabs, Hilton pedal, Steeler's Choice seat, Bessdang Gizmos from Dale Hansen, and a few other widgets and doodads.
I may not sound good, I just don't wanna sound bad. |
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