Defender Power Supply

[tb lilley]

I recently acquired a Defender (2 days before Christmas). It's sat on its own ever since. I've been busy with other projects, so it's had no more than a cursory glance thrown its way over the last couple of months. 

This is the third Defender I've owned. I've got a daft habit of selling them to finance other cabs, then buying another after a couple of months. 

This particular model has been operated in the US. Which means it needs converting to run on UK mains. A fairly simple operation. Swap a couple wires on the AC harness, stick the right fuse in, and change the varistor stuck on the front of the AC line filter.

Anyway, sleeves rolled up, and time to see what's inside:

Good news. Everything required is there. Time to take a closer look:

Hmmmmm ...... Could do with a clean.

AC harness:

This is not ideal. Power lead for monitor cut and removed. Not sure what's going on with the black and white wires either:

Anyway, time to give the transformer block a bit of a scrub (kitchen sink, cillet bang) and see how it comes up:

Nice and clean. 

As I was going to replace the varistor on the line filter I took the opportunity to put a new filter in too:

I always like to rebuild the linear power board on Defenders. Always put in new caps, new regulators, new bridges, job lot. Here's one I prepared earlier. For this one I've swapped out a resistor and stuck an adjustable pot in:

This allows the +5 to be dialled in to exactly +5 on the boards. Handy.

Anyway, here it all is, stuck back together:

While I was at it I also stuck a new connector on (from transformer to the linear input) as the old one was a bit burned up and had seen better days.

And here is the finished article:

Includes a new AC harness (with power lead for monitor), new on/off switch, new interlock. So .... a decent set of working boards and I should be good to go.

 

[DanP]

Very nice work, how's the cab itself? Is it in nice shape or does that need work also?

Dan

 

[tb lilley]

The cab is a bit of a shed really. I'm toying with the idea of sanding the whole thing down, filling, painting, and using stencils. But it's an outdoors job really, so will have to wait until spring / summer.

There again, it's not too bad .... Has a nice silver coin door, and the side art is pretty much intact. Dunno. I'm in two minds. There's sign of some damp / damage right at the bottom of the cab on the front. Not sure if it is damp though, and the other three sides (at the bottom) are fine.

I need to strip it right down, get it outside, stick loads of wood hardner on the front damaged piece, fill, sand, paint, and see how it looks. If I get away with it I'll touch the rest of the cab up rather than do a full restore.

It's a funny old cab. The control panel is sparkling, as is the marquee and bezel. I'm hoping a small repair to the front, then get it up off the ground with some new legs, and it'll be good to go. The boards are out for repair, due back soon. Cab bought as a shell, but I had a spare set of boards (non working) anyway. Also have a full repro wiring harness to connect it all together.

tb lilley2012-02-18 20:14:42

 

[Judder]

That's great information as yes I've just done the same and shipped a Defender cabinet in from Texas which is currently configured for US 110 Volts.

Do you have any more details on which wires should be used versus UK 240 and the variable resistor you added to yours?

Many thanks!

 

[tb lilley]

There's not much involved to convert from US to UK.

Stick a 250v fuse in place of the 125v one (next to the transformer). The varistor needs to be 275v (it's soldered on the AC input to the AC filter).

After that it's a case of swapping a couple of pins on the molex that plugs into the transformer.

For US operation the molex has 2 jumpers: 6P1-2 to 6P1-6, and 6P1-4 to 6P1-5.

For UK operation only single jumper is required from 6P1-2 to 6P1-5.

– so … to convert from US mains to UK mains you can simply snip the two jumpers then join / solder the wires from 6P1-2 to 6P1-5.

Pics might help:

Jumpers are the red and white wires (this currently wired for US):

And here it is, wired for UK:

That's a pretty scruffy way of doing it. So I removed pins and did a proper job:

Good luck!

 

[Judder]

Perfect!

Many thanks and superstar response - pictures definitely help and I'll be going the way of unpicking the pins with a tiny watch screwdriver I think and re-routing them around (did this to rewire a whole door on my TVR so quite good at it by now!!! )

Will let you know how I get on

Alex

 

[Judder]

Hi Again

Quick question on the Power Line Filter - looks like it is one of these but wondered if you knew off the top of your head?

http://docs-europe.electrocomponents.com/webdocs/0d69/0900766b80d69d8b.pdf

or whether one of these might make sense on the back of the cabinet instead?

http://docs-europe.electrocomponents.com/webdocs/002a/0900766b8002a1b5.pdf

 

[andyman]

Top one Alex, bottom one would be sacrilege

 

[Judder]

Hi Andy

Thanks for your reply and I hear you re: keeping it original

FYI and for anyone else interested, I have started a website for the rebuild of our Defender and would welcome any comments as we update the parts of the machine as we update it!

http://www.thedefenderproject.com/

Still to come:

- unboxing

- power supply

- screen

- cabinet fixing

- board testing

and a whole lot more by the looks of it!!!!

 

[Judder]

BTW forgot to mention would really love everyones help with our restoration as we are _really_ starting out a new with this one!!

Many thanks

Alex

 

[guddler]

How much has this Defender from Texas that needs restoring set you back? I'm more than just a little curious why you'd get one in from the US that needs restoring when there are so many over here (that also need restoring). I can understand not buying a £1500 fully restored one over here but surly it must have been a lot to buy it and get it over here?

Unless I missed it, I didn't see prices in your write ups on your site.

 

[Judder]

Hi Guddler

Too much is probably the answer, but sometimes you start down these rabbit holes and never know where they are going to go!

Still it's here, and I'm committed to getting it working so if I can get some advice from the people who know here to make it then that would be perfect.

One more saved, regardless from where, is probably a good thing

 

[Judder]

Hi everyone

Just a quick update that actually we have room for a Joust restoration (from the UK hopefully!) if anyone has one going?

Kindest regards

Alex

 

[Judder]

Stick a 250v fuse in place of the 125v one (next to the transformer). The varistor needs to be 275v (it's soldered on the AC input to the AC filter).

Right - I've been making (slow!) progress and cleaned the whole PSU, tested all the fuses and connectivity of their mounts of the circuit board and am ready to re-assemble.

Googling the 'what I thought was a resistor soldered on the front of the Power filter' it is a GE V130LA10AD Voltage Dependent Resistor and according to the GE data sheet, it's only good up to 130VAC so I'll need a 240VAC one as you say above.

I'm thinking something like this one rated at 275V would probably be the best thing??

The PowerFilter seems to be rateable for 115/250 VAV so I think I should be able to use that OK?

Then last a 240V fuse which I'm guessing Farnells/RS should be able to supply - just a regular 240V fuse I'm guessing?

Update: The fuse I have is made by 'Littel Fuse USA' and says [as far as I can read]

3/3 3AG

3A 250V

which would leave me it is rated at 5Amps up to 250Volts so should be OK?

Any sanity checking much appreciated!

Judder2012-04-05 10:10:30

 

[guddler]

That all sounds correct to me. It's normal to have to replace the varistor for a UK spec one.

 

[guddler]

Just read your edit. Check in the manual for what amperage fuse you need for UK voltage. Its probably different (lower?) but I'm not speculating on that one for obvious reasons!!

 

[Judder]

Thanks for the reply Guddler and I hear you re: the fuse - I will go and have a good read now!

Alex

 

[Judder]

Just read your edit. Check in the manual for what amperage fuse you need for UK voltage. Its probably different (lower?) but I'm not speculating on that one for obvious reasons!!

Both the Defender schematics, and the Stargate instruction manual I have rate the fuse as:

- Fuse, 3ASB, 115V (Stargate)

- Line Fuse 3AMP 115/V (Defender)

but guessing both of these are US manuals and don't reference a UK equivalent.

That said, the fuse is in-line between the Live wire, and I checked with the pictures above and the UK lead has the Brown (Live) connected to the Fuse, and the Blue (Neutral) connected directly to the power supply filter.

Would seems strange that the fuse we have is 3Amp 250V though if it has a US plug connected as it does however 3AM UK 240V fuse should be what we need.

 

[Judder]

Hi everyone

Quick question (again, apologies!) as I'm about to start the rewiring of my US -> UK Power Transformer this weekend.

Does anyone know of a 'nice' way to mount the varistor so that it doesn't have bare metal contacts carrying 240V odd in the exposed air?

The power filter I bought has nice covered terminals, and I bought covered crimp plugs to match, so with those on it should be safer.

I've taken a couple of shots here in case anyone has good ideas [or whether we can just not use it?]

http://www.thedefenderproject.com/?p=70

 

[andyman]

Could always use the fibreglass/polyester braided sleeve, as was original

Andy.