[vcf-midatlantic] Repairs to a Heath WH19 Terminal
perkins.jason at gmail.com
Mon Mar 27 12:03:44 EDT 2017
It's an MJ2841
I ordered one from eBay. We'll see what the tracking says. If it won't get
here in time I can pick up an NTE-284 tomorrow at a local place.
On Mon, Mar 27, 2017 at 11:49 AM, Matt Patoray via vcf-midatlantic <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> Jason, what is the transistor model? on the schematic that just looks like
> a house part number?
> On Sun, Mar 26, 2017 at 11:57 PM, Jason Perkins via vcf-midatlantic <
> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> > With some extra off-list help from Dave I found that the main power
> > transistor Q213 is leaky.
> > Now the challenge will be to find one of those, or something that can
> > without having to pay $50 in shipping!
> > -J
> > On Sun, Mar 26, 2017 at 4:58 PM, David Gesswein via vcf-midatlantic <
> > vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> > > On Sun, Mar 26, 2017 at 04:51:30PM -0400, Jason Perkins via
> > > vcf-midatlantic wrote:
> > > >
> > > > After the regulator I measure 61.5 volts DC w/ .35v to .41v of ripple
> > at
> > > > 60hz. - sounds like it's not regulating much
> > > >
> > > > Reading the manual more, it doesn't use an integrated voltage
> > > > "The unregulated 65-volts DC from the power supply circuit board
> > > the
> > > > video circuit board at plug P202, pins 2 and 3.
> > > > Assume that the Terminal has just been turned on and the output of
> > > > +53-volt regulator is at zero volts.
> > > >
> > > Didn't have time to look at the schematic but if you are reading 61.5V
> > > the 53V output the regulator probably isn't regulating so its not
> > filtering
> > > the ripple. Are you able to understand the circuit to see how it should
> > be
> > > regulating and that the correct output should be close to 53 volts?
> > >
> > --
> > Jason Perkins
> > 313 355 0085
> Matt Patoray
> Owner, MSP Productions
313 355 0085
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