Saturday, Febuary 26, 2011

Attendees: Ron Williams, Bob Erickson, Stan Paddock,  Ed Thelen, Jim Hunt, Ron Crane 

Visitors: Goerner, Matthias (one of our 1401 volunteers) brought in two visitors. After visiting us, they went into the main exhibits and were there until the museum staff told them they had to leave since the museum was closing.  Ed Thelen provided automobile transportation to and from the Museum for the three of them.

We also had four museum visitors who found our door open and came in to see what was going on. 
They got the informal briefing on the equipment in the room.
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Ron Crane has been studying the 'power factor' for the input power on the German machine. The top picture is a test setup where high voltage capacitors were connected to verify the amount needed to correct the power factor.

To measure the power factor, the current through a leg of the three phase power is connected to an oscilloscope along with the voltage. If they both peak at the same time, you have the desired power factor of 1.

We ran tests on the power going into the Connecticut machine and the German machine.  The results are shown below.

German IBM 1401, 1402, 1403, 1406, (1) 729	220/380 3Ǿ 50 Cycles	10.85	2,387.00	53.06%
	220/380 3Ǿ 50 Cycles	7.05	1,551.00	34.47%
	220/380 3Ǿ 50 Cycles	2.55	561.00	12.47%
Total of three phases		20.45	4,499.00	100.00%
Connecticut IBM 1401, 1402, 1403, 1406, (3) 729	120/208 3Ǿ 60 Cycles	14.77	1,772.40	34.37%
	120/208 3Ǿ 60 Cycles	12.20	1,464.00	28.39%
	120/208 3Ǿ 60 Cycles	16.00	1,920.00	37.24%
Total of three phases		42.97	5,156.40	100.00%

We suspect the power factor  shift is related to the unequal loading of the three phases of power going into the German 1401. Research continues.

Bob Erickson is continuing to bring the IBM Model B transmitting typewriter back to life. We were able to get a new typewriter ribbon for the machine and installed it. When we plugged it in and tried to type, no ink transferred to the paper. At lunch, Bob figured out the primary problem. The nearest 110V socket to where the typewriter is located is on the back of the German 1401. That machine runs on 50 cycle power not the normal 60 cycle power. So the power roller that drives the print hammers was running at 50/60 normal speed.

After lunch, we plugged it into 60 cycle power and it worked much better. By the end of the day, Bob got almost all of the type hammers to work as designed.

Ron Williams was checking out the basic timing circuits on the German machine.He noticed a waveform that was not correct. While it did not seem to bother the operation of the machine, it was still wrong.

Ron and Jim Hunt found the card suspected of causing the problem. Jim replaced the transistor and the signal got worse! The question of what 'new' transistor matched the functionality of the old transistor spiked the interest of Ron Crane. The second picture shows Ron Crane testing available transistors to see if he can match the functionality.

Keypunch # 3 miss fed another card again while Bob Erickson and I were watching. It does this about one time out of a hundred. Bob and I took the feed mechanism apart and replaced the feed knives with feed knives from the keypunch carcass. Appears to work fine now.

When I arrived to the Computer History Museum on Saturday,  I could not access the external employee door or the two doors into the 1401 Restoration lab. I had to get Museum staff to bring a key and unlock the two doors to the  1401 Restoration lab. We left the doors blocked open all day since we could not get back in if we closed them over lunch. We have been told that this issue is being addressed.

Stan Paddock

Wednesday Febuary 23, 2011

Attendees: Ron Williams, Bob Erickson, Robert Garner, George Ahearn, Stan Paddock, Bill Flora, Frank King,  Don Luke, Douglas Martin, Bill Newman, Joe Preston,  Ron Crane

Frank King heard a noise from the IBM 1403 attached to the Connecticut system.

After removing the main cover and other parts surrounding the top blower motor

 , he decided the noise was coming from the IBM 729 tape drive behind the IBM 1403.

Frank then put the 1403 back together and started looking for the noise in the IBM 729 tape drive.

Don Luke continued his efforts to build a course outline to teach the IBM 401 internals.

Ron Crane continued his evaluation for the power going into the German 308 volt 50HZ system.

The term Power Factor defines if the current waveform peak occurs at the same time as the voltage peak. The picture below is of one of the three legs going into the German System.

While this leg looks good, the other two legs show a considerable shift in the power factor.

Ron had brought in some small capacitors which he hooked to the first leg. The sum of theses capacitors (25Uf) cut the problem in half. With the installation of three capacitors of the correct size, the load to the power converter can be reduced by at least a kilowatt. This excess power has to be removed from the room via at least another kilowatt worth of Air Conditioning.

(to be continued.)

 

Robert Garner and George Ahearn discuss some historical publishing regarding early computers.

Ron Williams and Don Luke discuss the old times when the IBM 1401 was considered "State of the Art".

Ron Williams, Bob Erickson and Bill Flora look for a small missing "C" clip for the Connecticut 1402.

Bill Newman, Ron Crane, Bob Erickson and George Ahearn discuss the way they think an old IBM Model "B" transmitting typewriter works.

Stan Paddock

Wednesday Febuary 16, 2011

Attendees: Bill Newman, Bill Flora, Bob Erickson, Douglas Martin, Robert Garner, Frank King, George Ahearn, Glenn Lea, Joe Preston, Ron Williams, Stan Paddock

 George Ahearn and Stan Paddock are shown trying to figure which key hits which type bar and makes which connection underneath the keyboard. This "Transmitting" typewriter will be used as an IBM 1407 attached to the Connecticut IBM 1401 system.


Bill Newman has been given permission to look at some "Transmitting" typewriters in the warehouse in Milpitas. From inventory pictures these have data cables attached. The machine we have does not have same.

 

The picture above is for one section of the type bars. Thanks to Ron Crane for the high quality picture.

Joe is continuing his work on the third 729 attached to the German IBM 1401 system.

Ron Crane came in and helped up with our documentation of the power used in the IBM 1401 Restoration Room. Ron explained the difference with three phase delta connection and three phase Y connection. Ron explained the functionality of the power converter. Input 208 volts three phase delta 60 cycles per second with the output three phase Y 308 Volts 50 cycles per second. We also determined the power converter is only 56% efficient.

If you are interested in the data, you can find it on my web site at: http://www.paddockdrayage.com/OneAtATime/CHM1401RoomPower.xls

Robert  Garner spent time verifying that the work we are performing on our systems is within the scope of what IBM did back in the 1960's. Since he works for IBM, this seems like a reasonable thing to do.

Bill Flora checks out the card reader of the Connecticut IBM 1401 system. This machine has given us problems from the day we first powered it up.

We have identified and fixed several problems and fixed them. We are hoping that we have fixed the last problem.

Ron Williams is checking for:

1. That the fans are operational.

2. That he has chased the last varmint from the machine.

Bill Newman and Douglas Martin are looking on-line to find replacement transistors for the ones we need on the Connecticut IBM 1401 system.

 

Saturday, Febuary 12, 2011

Attendees: Ron Williams, Bob Erickson, Jim Hunt

The database for the door locks has changed again. The team could not get in the outside door or the two doors to the 1401 restoration room via the CHM supplied access card. The team entered via the lobby door and the person manning the lobby desk used a key to open the 1401 room doors.

Ron Williams exercised the IBM 1402 readers and punches on both the Connecticut and German machines. Ron pointed out that to not use these functions is much like leaving the machines in a warehouse putting dents in the rollers. (Good Point)

Ron suggested that we do this exercise every week.

Jim Hunt continued his power supply work. He is a bit frustrated by having failures after fixing the unit. Third time is the charm.

Bob Erickson was doing the same type of exercise Ron was doing on the IBM 1402s but Bob was doing it on the IBM 077 collator. Bob is also working on a demo for the IBM 077 that can be used for demos.

Stan

Wednesday Febuary 9, 2011

Attendees: Ron Williams, Bob Erickson, Robert Garner,  George Ahearn, Stan Paddock, Frank King, Bill Newman, Joe Preston,  Ed Thelen, Allen Palmer, Ron Crane

Visitors: Allen Palmer's wife and two CHM docents looking for sample punched cards.

George Ahearn, Stan Paddock and Bill Newman outlined the architecture for the IBM 1407 typewriter.

 Stan Paddock fixed the CHM wheelchair that he and Ed Thelen broke last week. It was returned to the CHM lobby.  

Allen Palmer continued his work on tape drive number two of the German machine.

Joe Preston continued his work on tape drive number three of the German machine.

George Ahearn interrupted the normal date sequence of the time clock correcting it to the correct month.

Ron Crane explained to Stan Paddock, Bill Newman and George Ahearn the complexities of the three phase power being delivered to the German machine. This includes the conversion of 60 cycle 208 volt power to 50 cycle 208 volt power. It was determined that while there are more efficient ways to to perform the conversion task today, it is not worth the effort to make a change.

Robert Garner brought in his laptop so we could view videos of the upcoming IBM 100th celebration.

Stan Paddock

Wednesday Febuary 2, 2011

Attendees: Bill Newman, Bill Worthington, Bill Flora, Bob Erickson, Douglas Martin, Frank King, George Ahearn, Glenn Lea, Joe Preston,  Allen Palmer, Ron Williams, Stan Paddock

 Joe Preston is making progress on the third IBM 729 tape drive. It will now automatically :

1. Load the tape into both vacuum columns

2. Bring the head down on the tape

3. Rewind the tape to the beginning tape indicator

This is all perfectly normal.

Now if it did not continue by raising the tape head and unloading the tape..

There is always next week.

Upon occasion, Robert garner will explain how modern computers work. Or how SUN built the first real computer. Or how much raise we can expect at the end of the month.

We had a pair of guest who decided to see the Computer History Museum because their flight to New York was canceled. They were looking for the BABBAGE machine but wondered into out room by accident. 

Stan