[T3] Two Tests

[Jim Adney]

This afternoon I decided to get off my butt and do 2 things that I had been 
postponing for way too long.

First, I needed to replace the voltage regulator on my ratty daily driver, the 
beige '73 Square. I've been getting those loud clicks from the old one that 
always preceeds their death. Best to change it now, before any harm is 
done. This was my chance to try one of the new Bosch electronic VRs.

I havn't been too excited about these, because they have a large upper shell 
which is entirely at generator output voltage. Seems like an invitation to 
shorts.

In the process of installing this new VR, I ran across a few other problems 
that I think are equally troublesome.

1) There's no provision for attaching the ground wire. There is a pair of extra 
screws on top that turn out to be grounded. They're not designed or intended 
to be used as grounds, but that's what I did.

2) The stud where we're supposed to attach the D+ wire, the generator 
output, has a hex nut on top that's larger than 9 mm and smaller than 10 mm. 
Could it be 3/8"? I don't know, but I managed to tighten it anyway.

3) That top shell, which is at generator output (D+) voltage is too close to the 
inner side wall of the body. There's a piece of vinyl there on my Square, but 
if that cuts thru, I'll have a short. This is all made worse by the "flare" at the 
bottom of the shell. I will put some thin insulator there, to keep this from 
happening. If I were doing it over, I'd slot the mounting holes so the VR 
could slide 1/4" farther inboard, and maybe see if I could flatten the flare a 
bit.

Once installed, it seems to regulate well, but I'll need more experience with it 
to know better.

The second task was to go thru my stash of FI brains and test a few '73 048 
brains, to make sure I had some that seemed good. I think I came up with 5.

I pulled out the one in the car, that had been working fine for the last 3 
years, and tried each of my others in turn. Those tests were short, but my 
original '73 still seemed to run extremely rich. So I'll set that one aside, 
marked as bad. Apparently there is something that can go wrong with that 
version. While testing, I noticed that this last generation has 2 boards, an 
upper and lower. If I'd noticed that before, I'd forgotten. I'll have to look at 
some earlier versions to see when that started, but I don't think the ABCD 
versions were that way.

When I was finished, I reinstalled the one that has been working well for the 
past 3 years.

BTW, for those who have been following William's quest, a D pressure 
sensor was for the Euro '72s. Everything else (brain & distributor) that I can 
see looks to be the same as what we got here in the US.  

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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