[vcf-midatlantic] Repairs to a Heath WH19 Terminal
mspproductions at gmail.com
Mon Mar 27 19:52:18 EDT 2017
Awesome! Always good when another piece of gear is saved!
Sent from my iPhone
> On Mar 27, 2017, at 7:34 PM, Jason Perkins via vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> New power transistor, and now B+ is spot on and stable. No more wobbles!
> On Sun, Mar 26, 2017 at 11:57 PM Jason Perkins <perkins.jason at gmail.com>
>> 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 sub,
>> without having to pay $50 in shipping!
>> 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 regulator
>>> "The unregulated 65-volts DC from the power supply circuit board enters
>>> video circuit board at plug P202, pins 2 and 3.
>>> Assume that the Terminal has just been turned on and the output of the
>>> +53-volt regulator is at zero volts.
>> Didn't have time to look at the schematic but if you are reading 61.5V on
>> 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
> Jason Perkins 313 355 0085 Sent from my iPhone
More information about the vcf-midatlantic