19 Mar
2017
19 Mar
'17
2:39 p.m.
Hey guys, figured it was time for an update on the LGP-30 resuscitation.
Some further detective work found a leaky 1500uF cap in one of the B+ supplies which was
causing the 'surging' issue on the scope. For good measure I replaced all six 1500
and 3000uF caps even though ripple was low. Better safe than sorry and if it means pulling
that chassis and its covers again, all the better. I attempted to weigh it on my shipping
scale, but it only registers to 100 lbs and the indicator flew right past that.
There had been a small thermal event in the AC junction box that the twist lock connector
mounts to, and I suspect it occurred pre-60's refurb. It's not too surprising as
the wiring on the computer side is aluminum and the feed is copper. The box needed
replacing but was a unique Hubbell variation of a std 4" box with special ears. I
couldn't find anything even close to that at any of the supply houses online, probably
because it violates today's conductor fill rules (it's only 1" deep but the
socket consumes most of that depth and 75% of the area). I eventually settled on
drilling/tapping a standard box and cleaned up the wiring.
The sequencer unit is now working correctly after I found an NOS relay to R&R contacts
with. The blower is still steady and quiet with its new bearings, and no issues (knock on
wood) with the drum after greasing the end bearing, belt and 'tightening' up the
tolerances on the timing and short register heads.
Some good news- I now have three horizontal lines on the scope, rock solid and where they
should be. I can get the occasional pattern for Instruction contents, but Order and
Accumulator still aren't reading/writing/displaying. All in good time.
http://radar58.com/LGP30/wp-content/uploads/2017/03/lgp.jpg
Even better news is that the three timing tracks appear to be intact on the drum and the
supporting hardware is working.
http://radar58.com/LGP30/wp-content/uploads/2017/03/scope-e1489957963176.jpg
(1, 2 and 3 correspond to S1, S2 and S3)
Now to investigate those short registers... -Cory
19 Mar
19 Mar
3:33 p.m.
Impressive progress! Well done!
73 Eugene W2HX
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Cory Heisterkamp via
cctalk
Sent: Sunday, March 19, 2017 5:40 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: LGP-30 Update
Hey guys, figured it was time for an update on the LGP-30 resuscitation.
Some further detective work found a leaky 1500uF cap in one of the B+ supplies which was
causing the 'surging' issue on the scope. For good measure I replaced all six 1500
and 3000uF caps even though ripple was low. Better safe than sorry and if it means pulling
that chassis and its covers again, all the better. I attempted to weigh it on my shipping
scale, but it only registers to 100 lbs and the indicator flew right past that.
There had been a small thermal event in the AC junction box that the twist lock connector
mounts to, and I suspect it occurred pre-60's refurb. It's not too surprising as
the wiring on the computer side is aluminum and the feed is copper. The box needed
replacing but was a unique Hubbell variation of a std 4" box with special ears. I
couldn't find anything even close to that at any of the supply houses online, probably
because it violates today's conductor fill rules (it's only 1" deep but the
socket consumes most of that depth and 75% of the area). I eventually settled on
drilling/tapping a standard box and cleaned up the wiring.
The sequencer unit is now working correctly after I found an NOS relay to R&R contacts
with. The blower is still steady and quiet with its new bearings, and no issues (knock on
wood) with the drum after greasing the end bearing, belt and 'tightening' up the
tolerances on the timing and short register heads.
Some good news- I now have three horizontal lines on the scope, rock solid and where they
should be. I can get the occasional pattern for Instruction contents, but Order and
Accumulator still aren't reading/writing/displaying. All in good time.
http://radar58.com/LGP30/wp-content/uploads/2017/03/lgp.jpg
Even better news is that the three timing tracks appear to be intact on the drum and the
supporting hardware is working.
http://radar58.com/LGP30/wp-content/uploads/2017/03/scope-e1489957963176.jpg
(1, 2 and 3 correspond to S1, S2 and S3)
Now to investigate those short registers... -Cory
4:30 p.m.
<snip>
http://radar58.com/LGP30/wp-content/uploads/2017/03/lgp.jpg
Even better news is that the three timing tracks appear to be intact on
the drum and the supporting hardware is working.
http://radar58.com/LGP30/wp-content/uploads/2017/03/scope-
e1489957963176.jpg
(1, 2 and 3 correspond to S1, S2 and S3)
Now to investigate those short registers... -Cory
great news!
Bill
6:44 p.m.
Sweet!
Marc
On Mar 19, 2017, at 2:39 PM, Cory Heisterkamp via
cctalk <cctalk at classiccmp.org> wrote:
Hey guys, figured it was time for an update on the LGP-30 resuscitation.
Some further detective work found a leaky 1500uF cap in one of the B+ supplies which was
causing the 'surging' issue on the scope. For good measure I replaced all six 1500
and 3000uF caps even though ripple was low. Better safe than sorry and if it means pulling
that chassis and its covers again, all the better. I attempted to weigh it on my shipping
scale, but it only registers to 100 lbs and the indicator flew right past that.
There had been a small thermal event in the AC junction box that the twist lock connector
mounts to, and I suspect it occurred pre-60's refurb. It's not too surprising as
the wiring on the computer side is aluminum and the feed is copper. The box needed
replacing but was a unique Hubbell variation of a std 4" box with special ears. I
couldn't find anything even close to that at any of the supply houses online, probably
because it violates today's conductor fill rules (it's only 1" deep but the
socket consumes most of that depth and 75% of the area). I eventually settled on
drilling/tapping a standard box and cleaned up the wiring.
The sequencer unit is now working correctly after I found an NOS relay to R&R
contacts with. The blower is still steady and quiet with its new bearings, and no issues
(knock on wood) with the drum after greasing the end bearing, belt and
'tightening' up the tolerances on the timing and short register heads.
Some good news- I now have three horizontal lines on the scope, rock solid and where they
should be. I can get the occasional pattern for Instruction contents, but Order and
Accumulator still aren't reading/writing/displaying. All in good time.
http://radar58.com/LGP30/wp-content/uploads/2017/03/lgp.jpg
Even better news is that the three timing tracks appear to be intact on the drum and the
supporting hardware is working.
http://radar58.com/LGP30/wp-content/uploads/2017/03/scope-e1489957963176.jpg
(1, 2 and 3 correspond to S1, S2 and S3)
Now to investigate those short registers... -Cory
2741
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participants (4)
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billdegnan＠gmail.com -
coryheisterkamp＠gmail.com -
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w2hx＠w2hx.com