| '69-'70 Kustom 100 2 power cord upgrade [message #29173] |
Fri, 17 November 2023 07:03  |
backlineguy
Messages: 20
Registered: November 2023
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Junior Member |
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Hello, I'm new here - glad that I found it! - I just acquired a '69-'70 Kustom 100 (2) in amazing condition, and I'm wanting to upgrade the power cord from the 2-prong to a grounded 3-prong...I found this forum and a similar question/answer segment from 2013 I think, so rather than try and reply to that thread, I'm trying to ask through my own...I'm thinking replacing the cord is a good idea and safer than as-is, but it does work fine as-is too...isn't there an adapter of somekind that can fit over the 2-prong plug that would help, even if it did not totally solve the polarity issue? IS polarity an issue?
I've seen advice on how to do this, and I need to say I have not even opened the chassis yet to look inside, but...I'm thinking that the black and white wires will need to be connected to where the black and white wires were connected on the 2-prong cord, and the green will need to go to the chassis. My real question is about this "Death Cap" I've read about...where is it? Why is it referred to this way? Can anyone post pictures of one? Can it just be clipped and removed? If so, will the 3-way 'on-off-on' polarity switch still power the thing on and off?
I've had quotes from repair shops of $200 or so to replace the power cord, and I just can't bring myself to pay that much...the amp head and cab are in mint condition, and it really sounds great too, so I don't want to screw it up, so any help y'all can offer will be greatly appreciated. Thanks in advance.
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| Re: '69-'70 Kustom 100 2 power cord upgrade [message #29174 is a reply to message #29173] |
Fri, 17 November 2023 17:07  |
stevem
Messages: 4774
Registered: June 2004
Location: NY
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Senior Member |
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Here's some details to what needs to be done, and while it does take some work and specialty tools 200 bucks seems high to me, and I live in NY!
You need a 3 wire power cable of the length you want to have.
I get a good quality ac extension cable from a hardware store.
You need a new bigger Heyco bushing to fit around the now bigger 3 wire cable.
You also need the Heyco bushing tool to remove the old cable and bushing, and of course you need the tool to install the new cable with its now bigger bushing.
You need a grinder to like I use to open up the chassis hole to take the bigger bushing , or you can use a good size rat tail metal file to open up the hole if there nothing on the inside of the chassis blocking your movement of the file.
You need a crip on wire ring to go on the green ground cable and a crimp tool or vise to put it on with.
[Updated on: Fri, 17 November 2023 17:08] Report message to a moderator |
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| Re: '69-'70 Kustom 100 2 power cord upgrade [message #29182 is a reply to message #29181] |
Fri, 24 November 2023 06:53 |
backlineguy
Messages: 20
Registered: November 2023
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Junior Member |
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the reverb tank is suspended from a couple of cross braces on top of the chassis, but after connecting the patch cables the reverb does not work...I did see that it's a 2 spring system and it's missing one spring...it has 031-0005-00 stamped on the tank, but no manufacturer or model name anywhere...if I wanted to replace this tank, what would you recommend?
[Updated on: Fri, 24 November 2023 12:50] Report message to a moderator |
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| Re: '69-'70 Kustom 100 2 power cord upgrade [message #29183 is a reply to message #29182] |
Fri, 24 November 2023 18:56 |
stevem
Messages: 4774
Registered: June 2004
Location: NY
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Senior Member |
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Direct drop in replacement reverb tanks can not be had any longer.
We have to go with one's made for a Musicman amp .
To work with Kustom amps the output jack on the tank needs to get grounded to the tank to shield it properly.
These tanks can be bought from Antique electronics and it's part number is p-rmod4fb3d1b.
Note that just like the original tank the output side of the replacement tank needs to be mounted the furthest away from the power transformer.
[Updated on: Fri, 24 November 2023 19:02] Report message to a moderator |
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| Re: '69-'70 Kustom 100 2 power cord upgrade [message #29184 is a reply to message #29183] |
Sat, 25 November 2023 08:07 |
backlineguy
Messages: 20
Registered: November 2023
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Junior Member |
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I found the tank, thank you.
Questions; When you say "To work with Kustom amps the output jack on the tank needs to get grounded to the tank to shield it properly."...please elaborate...there's a grounding wire on this old tank soldered to the tank case, and connected to a screw on one of those cross braces...is that what you mean?
The old 2-spring tank was missing a spring - would that cause it to quit? The RCA input/output jacks on the board do not appear to be labeled, but the patch cables are too short to cross...can I assume the closest jack connects to the closest jack on the tank?
The output jack is already at the opposite end of the chassis from the power transformer...
Is it possible to get a replacement long spring, or better to replace the tank? The tiny clip/hangers for the missing spring appear to be intact...
The old tank was mounted open side up, and the replacement tank says in the description that it's mounted open side down...does that matter?
The fuse is soldered in...what is the rating of the fuse so I can have a couple spares?...3A slo blow?
and finally, the new power cable's got Brown, Blue and Green/Yellow, not Black and White like the old existing cable...is Brown Black, and Blue White when I'm replacing the old 2-wire? I'll use the nut that the Death Cap is screwed down with as my ground after I clip it out...
thanks again for your patience with my dummy questions! I'd like to be able to share some images to you can see the chassis inside, but how can I add images here?
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| Re: '69-'70 Kustom 100 2 power cord upgrade [message #29193 is a reply to message #29188] |
Sun, 03 December 2023 06:20 |
backlineguy
Messages: 20
Registered: November 2023
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Junior Member |
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ok, yesterday was the day...finally removed the strain relief, fired up the soldering station, and replaced the 2-prong power cord with the grounded 3-prong on my '69 Kustom 100 2...also replaced the fuse block since the original fuse was soldered in...question there...I picked up some 1.5A fast blo fuses, but the existing fuse was a GJV3, so I inserted that into the new clips...and long story short, it works great...BUT the power switch that used to allow polarity change does not power on in both directions ( with the center position being OFF)...only one - which is really all I need, but any suggestions on why this is?
Also attempted to wire in a new reverb tank, added new RCA patch cables, but it does not work... with the reverb turned all the way down, if the head itself is jostled a bit, the usual spring reverb tank 'crashing' noise can be heard, but turning up the reverb knob does not produce any reverb...any suggestions on THAT one?
I remember you mentioning something about grounding - and the old/existing tank had a ground wire soldered to the outside and it was grounded to one of the cross braces...this new tank does not have this grounding wire...is that it?
Again, thanks for all the help on this one...I now have a beautiful, functioning - sans reverb - '69 Kustom 100 head with a grounded power cable...and the exterior tuck n roll on this thing is just beautiful too in charcoal ...
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| Re: '69-'70 Kustom 100 2 power cord upgrade [message #29195 is a reply to message #29173] |
Sun, 03 December 2023 07:22 |
stevem
Messages: 4774
Registered: June 2004
Location: NY
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Senior Member |
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Because while I have never measured the full current draw of a K100 there seems to be inaccurate fuse ratings for these amps.
For example in the schematic for the K100-5 ( the PA head ) the fuse is shown as 1.5 amps while all other K100 heads are shown with a 3 amp fuse.
A 50 watt amp ( which these really are ) does not need a 3 amp fuse.
If you look at all the k200B heads they all use a 3 amp fuse, yet have twice the output wattage as a k100.
Try the 1.5 amp fuse and play the amp loud to see if it pops, if it does there should then be no need to go any greater than a 2 amp fast blow type.
With a 3 amp fuse in there if there does develop a power supply / output stage problem then a bunch more parts will blow up before that 3 amp fuse lets go.
[Updated on: Sun, 03 December 2023 07:23] Report message to a moderator |
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| Re: '69-'70 Kustom 100 2 power cord upgrade [message #29196 is a reply to message #29173] |
Mon, 04 December 2023 12:16 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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The replacement reverb tank should have both input and output jacks grounded. If the input jack is not grounded, there will be no complete circuit and the tank will not be driven with any signal.
All plexi front amps use this same type of tank. In the latter metalfront amps, the drive circuit places the input coil of the tank in the feedback loop of the driver chip, so these tanks need the input jack isolated.
All standard Accutronics tanks (and most other manufacturers) use the same codes on the tanks. The fifth place character describes the input and output grounding schemes. A= Input and output grounded, C= Input isolated and output grounded.
If the tank you bought has a letter C in the 5th spot, then you will need to jumper the ground at the input jack to the chassis ground of the case.
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| Re: '69-'70 Kustom 100 2 power cord upgrade [message #29219 is a reply to message #29218] |
Sun, 28 January 2024 08:56 |
backlineguy
Messages: 20
Registered: November 2023
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Junior Member |
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Thanks Carlc...I'll definitely check them out, I appreciate the info. I've just been playing through it a lot, and really, really loving it. In my youth (15 yrs old) I really had no clue about tone, distortion, etc...I bought a 1968 Sunburst Strat from my girlfriend's older brother in '75 for $200, I'd turn the thing up loud, and that was about it! I kept that original K100 until I was 22, actually used it in the studio once as well, and the contrast between my Kustom and the lead players Fender amp was great... man, I spend a lot of time just admiring it too. It's like brand new cosmetically so it's a treat...I saw a black K100 B-2 I think it was ( 100w head and the 215 cab) with the tuck n roll - not even close to the same condition as mine...a few cigarette burns on the head, rips with the stuffing/foam showing through in a couple of places - dude was asking $1800...I paid 1/6 of that, so either that guy is dreaming, or I found the unicorn of K100's...
Either way, I'm incredibly happy and thankful to have mine.
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