Tag Archives: Caps

About Caps

One of the unantipicated tricky parts of trying to make my prototype look authentically oldschool is finding components that look correct for the period.  As we know, as technology advances things tend to get smaller, and indeed, capacitors in particular are much, much smaller for the same capacitance than they were 40+ years ago.

One cap that has really annoyed me from the beginning is the 100uf.  These are used all over the place in the TVT.  If you recall my ASCII encoder side project, you’ll recall just how tiny those 100uf caps were relative to the originals.  Here’s a pic of one for a refresher.  They are absolutely puny:

I realize my artist’s OCD is at play here, but still.  I want this thing to look right. These do not look right.  I mean, the ‘metal sausage’ look could be authentic.  Shortly after Christmas, an auction for an original TVT appeared (sadly, I lost it, but more on that in a future post).  The owner/builder, Roy, was kind enough to send me some photos of it.  It’s amazing to have some quality photos of an original.  This shot of the memory board shows that indeed, metal sausage caps were around back in the day:

But again, they are quite a bit larger, and they are not what Don used in the prototype.  For perspective, here is what the originals should look like:

They’re basically a mini can.  They have a very nice, flat top, cylindrical look.  The cap pictured is a vintage Siemens 100uf 16V.  These are all over my SWTPC equipment and appear to be similar to what Don used on the TVT.

I hunted and hunted for months.  Finally, I had some luck.  Somebody had these lovely ruby red Bakelite-style caps that were the exact same size and style as the Siemens I was looking for!

I couldn’t find any in any color other than red, but that was fine with me.  I’ve accepted from the outset that I was never going to get an exact copy of Don’s prototype internally.  There’s just too many unknowns and long discontinued parts.  But these will do!  I’ve ordered a whole bunch and will install them wherever 100uf are required, and also use them to replace the ones on my ASCII encoder to remove that bit of modernity.  Hopefully they work!