I see a lot of 7762 X61 tablets being sold on ebay. Is there anyone out there who can summarize the key differences between the models 7762 7763 7764 7767 7769?

I know there is a lengthy service pdf that probably shows the differences if someone is willing to wade through hundreds of pages. I'm hoping there's some "guru" out there who can give just the "cliff notes" version of the differences.

I also notice that Lenovo's description of the 7769 often says "based on the 7762." What does that mean? Does it have the limitations of the 7762, whatever they may be?

I've been able to push the memory of my 7764 to 8GB (two 4GB boards) with no problems. Is this possible with all the other models?

There's nothing complicated about the Lenovo ducumentation: http://www.lenovo.com/psref/pdf/ltwbook.pdf
All those types you mention are in there, 1 page per type.
In the PDF program, show 'Bookmarks' and you find it in seconds.
Most of the differences are: CPU speed, bluetooth Y/N, fingerprintreader Y/N, LCD-type, wifi type, OS type.
If you want specifics, there's no way around that list.

And 8GB is possible in every X61 or X61T (tablet).

Thanks for the link to that document. I'd not seen that before. It summarizes key features for some 7762, 7763, and 7767 types. But oddly, the 7764 and 7769 are missing. Furthermore, this document is more concerned with identifying which selectable features a specific sub-model has, e.g. 7762-5AU vs 7762-A67.

I am under the impression that the features you list (CPU speed, bluetooth Y/N, fingerprintreader Y/N, LCD-type, wifi type, OS type) are options on each of the models, and don't discern the architectural differences of the various models. Aren't there key hardware/architectural differences amongst the models?

READ those pages, it's all there.

OK, will do. But I'm mostly interested in 7764 and 7769 in comparison to 7762. Those two are absent in that document and all other documents on Lenovo's PSREF site. I've emailed the contact listed for that page in hopes of learning more.

Most of the data involved is confusing and essentially meaningless IMO.

Knowing the palette that you're interested in pretty well, here's how I'd go about it:

a) Decide on the screen type: do you want SXGA+ or XGA? If you are OK with XGA, touchcreen or not?

b) Choose the CPU: most of the machines in circulation have a L7500 which works fine in my experience. If you feel that you *really* need L7700, it might be a longer search, especially if your primary requirement is a hi-res screen.

Everything else is upgradeable on DIY basis...without even breaking a sweat, or your piggy bank...

Again, you're talking optional features. I want to know, for example, what the difference is between a 7769 and a 7762 that have identical features (same screen, cpu, drive, bluetooth, wireless, etc). What are the differences between the base hardware?

None.

Warranty coverage would be the only thing, and I'm talking about IWS which is not something you'd be concerned about.

Those model numbers are only a part of the picture. The whole picture - and the only one that matters - is the full 7-character designation which is telling you *exactly* what you're looking at...for instance:

ThinkPad X61 Tablet (7762-95U)
L7500(1.6GHz), 1GB RAM, 80GB 5400rpm HD, 12.1in 1400x1050 LCD, Intel X3100, Intel 802.11agn(n-disabled), Bluetooth, Modem, 1Gb Ethernet, Secure chip, Fingerprint reader, 8c Li-Ion, WinVista Business

vs.

ThinkPad X61 Tablet (7762-54U)
L7500(1.6GHz), 1GB RAM, 80GB 5400rpm HD, 12.1in 1024x768 LCD, Intel X3100, Intel 802.11agn(n-disabled), Bluetooth, Modem, 1Gb Ethernet, Secure chip, Fingerprint reader, 8c Li-Ion, WinVista Business

Hope this clears it...

Well that's good news. I have about 6 thinkpads of various 776* models. If I need to replace something, like a fan unit or system board, I can swap in a part from a different 776* model?

Yes.

One exception to this rule would be any xxxx-CTO system. CTO = Configure To Order, in other words, a custom build that will not appear in the ltwbook.pdf file. For those kinds of systems, you may be able to determine the hardware setup by doing a Parts lookup but the information returned is a little bit cryptic. For example, here's one of my X60 systems (1709-G3U):

Mfg P/N	FRU P/N	Description					Serviceable
39T2711	39T2631	HDD60 SATA					Yes
39T7234	39T7265	KEYBOARD X60 NMB USE				Yes
42W7689	42W7697	T7200 OA2					Yes
92P1168	42T4505	BATT4SCAN					Yes
39T2787	39T2711	HDD 60GB					Yes
13N7095	13N7096	FLT PNL DS LCD12XGA SMSNG			Yes
92P1160	92P1159	LITEON65W					Yes
36P3366	40Y8403	1GB PC2MEM					Yes
39T0494	39T0495	ADONIS MDC					Yes
39T2766	41W0025	TRYG B60 TOSHI					Yes
39T5670	0000000	CALISTO (BDC-2) ADAPTER:WIRELESS COMBO A	No
40M8787	0000000	GBM APP:BOMS, NOT SHIPPABLE ACROSS BORDE	No
29R7077	NOTAFRU	COA LABEL, WINDOWS XP-PROFESSIONAL EDITI	No
42T0852	42T0853	GOLAN MOW1					Yes

ref: http://support.lenovo.com/en_US/product ... ookup.page?