TP755C AC Adapters

[Martin Giles <Martin.Giles@COMINCO.com>]

I have been watching a number of theads concerning Thinkpad AC Adapters and would like to share a few things with the list.  It is a sad (and long) tail of woe.

First, in the last 8 months I have determined there are at least 3 different AC Adaptors for 755C, and I assume it is the same for other 755 variants.  I also discovered they are not all the same.

First one ....Model AA19210
I bought my TP755 in Jan 1995, it came with AC Adapter Model AA19210.  The TP end of the plug was a 4-pin jobby, with +ve, -ve, grd & Input Signal connections. In June 95 I discovered there was a recall on this unit (for date codes <9452) so I thought I would have it replaced.  Six months and many calls later I received the replacement unit (There are many advantages to to living in Vancouver, B.C. - dealing with AC adapter recalls is NOT one of them).

Second 0ne...FRU P/N 85G6689
This adapter was the new model, I was advised by IBM/Canada,  shipped with all new TPs ( a scary thought in retrospect).  It was great at first, thin wire to the TP, sexy Velco strap, etc...  Unfortunately I discovered that if you use the Thinkpad FUEL utility to cycle the NiCd's as we all do, or, try to recharge them AFTER starting Windows (Win 95 in my case) surprise, surprise it will not recharge. You have to power it down and let it recharge 'cold'.  I did not notice this before as I am fortunate to have a Dock II in the office.  Being keen of eye I looked at the little schematic on the unit and found it to have only 2 connections +ve, -ve, but no Grd or Input Signal leads.  In fact if you are careful you can remove the 4-pin 'square' plug at the end to reveal the two connections.  We also have some 360s which use this unit but with the cocentric 2-conductor plug (which are a pain).  I presumed the Input Signal connection must do something and called IBM/Canada.  With the help of an extremely helpful IBMer I managed to get one of the older, but functional units.

The third one....FRU P/N 49G2196
This one works just fine, has schematic indicating 4-pins, recharges like it should, is a bit bigger than the second one but it works.  Even made my own Velcro strap.

Hope this helps someone. If any Canucks are interested I can give them some IBM telephone numbers via E-mail ouside of this list

.......Martin (martin.giles@cominco.com)