IBM IBM 25-7 Help needed

Discussion in 'Electric Horology' started by matthiasi, Jul 25, 2019.

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  1. matthiasi

    matthiasi Registered User

    Dec 3, 2010
    331
    4
    18
    Male
    Clock Repair & Restoration
    Kelowna
    Country Flag:
    Region Flag:
    #1 matthiasi, Jul 25, 2019
    Last edited: Jul 25, 2019
    OK, so I'm working on my first IBM Master / Slave setup. It's in an old Post Office in the area and they want to keep the ol' gal going.

    The case tag shows Model 25-7 Ser.No - HM1466 . International Business Machine Co. Limited, Toronto Canada.

    Unfortunately, they can't locate the key to access the slave. I know the Master was not working correctly, but after winding it some and "helping to move the movement", I know it wanted to run and that the slave appears to be working.

    The movement's front plate is stamped E13274 on the upper, visible portion, with "International Made in England" just above where the coils are positioned.

    A number of the contacts appear to be misaligned, dirty, corroded etc.

    So, after cleaning and doing an overhaul (no bushing work required!!!), just some reworking of the wires & terminal ends due to cut strands / missing terminal.

    I now have the clock running for over a day in manual mode (I just wind the spring). Seems to be keeping good time.

    So, now for my questions:

    1. Is there supposed to be grease between the magnetic solenoid "ends" and the brass plate that is bolted to the winding arm? Me thinks there should be to reduce wear & tear and cut down on the noise somewhat.

    2. Attached to the anchor arbour, there is a large arm with the barrelled end weight, which contacts the upper left contact assembly. This arm is keeping the contact closed 100% of the time. Is this correct or does it require adjustment so that the contact is only closed when the pendulum swings to the one side?

    3. The two roller contacts are actuated by the cams - one set of two between the plates, the other is on the outside of the front plate. Should these be synchronized to actuate at the same time? If not, which one actuated first and how far apart should they be?

    4. The 4-pronged contact assembly arm on the lower left. As set up, the bottom contact is closed between 53 minutes (i.e.- 7 mins to the full hour), all the way through to 41 minutes (i.e.- 19 mins to the full hour). These are aprox., as the dial is not presently installed. The top contact closes between 52 to 53 mins (i.e.- from 8 to 7 mins to the full hour). Is this correct?

    5. I posted on an other thread about using 2 car batteries to get around 24VDC to run the automatic winding. I may just end up using a couple of LiPo's that I have kicking around instead. How critical is this 24V value? Just don't want to fry the solenoids...

    That's it for now, though there may be more...

    P1110748s.jpg P1200385s.jpg P1200387s.jpg P1220391s.jpg P1220390s.jpg View attachment 541890
     
  2. matthiasi

    matthiasi Registered User

    Dec 3, 2010
    331
    4
    18
    Male
    Clock Repair & Restoration
    Kelowna
    Country Flag:
    Region Flag:
    try the pic again...
    P1220404s.jpg P1220402s.jpg P1220401s.jpg

    P1220402s.jpg P1220402s.jpg
     
  3. matthiasi

    matthiasi Registered User

    Dec 3, 2010
    331
    4
    18
    Male
    Clock Repair & Restoration
    Kelowna
    Country Flag:
    Region Flag:
    So the movement I have on the bench at present is pretty much identical to the one that JAB60 has in this thread: IBM - IBM Master Clock Power Supply . The one I have does not have the jumper on the top of the case. However, this unit is driven through the electrical box that is permanently installed in the building where it is normally “at home”.

    I have this one running on a manually powered spring, outside of its’ case. It has been cleaned etc. and so far, mechanically, it’s running great. I got around 14 hrs overnight and it hadn’t stopped. So, happy on this point.

    When I follow Edwardo’s advice from the other thread, I only get a partial success.

    I can apply 22.5 volts (6 cell LiPo, 6000mah è so, it has enough juice) across the coil / solenoid and it does actuate and wind the clock. I can't leave the wires there though, for obvious reasons. So I know the coil is good.

    When I mount the positive on post 3 (pics above), the negative on the Post for the minute contact, where cables 4 & 5 meet, I do get the trigger every minute, but it dies at the second contact from the top of the “four pronged” points. Is there a wire missing on this unit? Am I missing something – I get the feeling I’m going in a circle… L

    I thought that this 4 pronged contact set, being driven by the cam on the hour pipe, was for the duration contact & advance switch.

    I would like to be able to test it in my shop to ensure that the contact points etc are properly aligned, before driving the 80 miles to install it… ;)

    Kinda hoping that someone would chime in here...
     
  4. matthiasi

    matthiasi Registered User

    Dec 3, 2010
    331
    4
    18
    Male
    Clock Repair & Restoration
    Kelowna
    Country Flag:
    Region Flag:
    OK, so this clock has been working great since the beginning of August.

    Now that we had the fall time change (the last one, perhaps, here in BC?), how do we change it here?

    I believe the Master clock can be readily turned back an hour. But, how do we change the slave?
    Does one have to forward it 11 hours using the fast forward switch in the control box? The control box is the original IBM one...

    Me thinks that the exact minute is not that important, as long as the slave is "fashionably late", so that the internal regulation can take place just before the next hour.

    Am I missing something?
     
  5. fdew

    fdew Registered User

    Jul 12, 2007
    233
    4
    18
    Only two ways to set the slave back. Stop the master for one hr, or set the slave ahead about 11 hours.
     
  6. matthiasi

    matthiasi Registered User

    Dec 3, 2010
    331
    4
    18
    Male
    Clock Repair & Restoration
    Kelowna
    Country Flag:
    Region Flag:

Share This Page