Thinkpads Forum

Soo i bougth a mint 755CX the VGA model, but apparently it does not have any sound.

While googling around i found an old spec sheet that said "Mwave DSP Upgrade 2420801" for the 755CX.

I also have a beaten up 760ED with mwave. Anybody know if the parts interchangeable?

welcome to the forum..

i have several 755C models..
CD, CDV, CE..
nice solid thinkpads and sort of classic, especially when you type on THAT keyboard.. you then see how sloppy current era keyboards really are..
i also have 701C system boards with the MWave chip.. these ARE soldered on..

i DO NOT think the MWave chip isw socketed so any swapping will require de-soldering the chip with little way to know if it will work from 760 series to 755 series..

you would be a far better man than I if you can desolder and re-solder that chip, but if you are dead set on trying, don't kill a good 760 series, get one of my chip containing boards and have at it..
if it works write it up, if it fails.. well, how will you know if the cause is a bad de-solder or resolder job or if the chip itself is kaput..

The Mwave chip is soldered, yes, but it's on a small board that plugs to the system board. That's why it's possible to replace the Mwave audio with an ESS 1688 on the 760XD.

However, looking at the HMMs of the 755 and 760 series, their Mwave cards have different FRUs, and seem to have different form factors. But since I've never seen a 755 (I had a 760XD a long time ago), I can't be sure.

BillMorrow wrote:welcome to the forum..

i have several 755C models..
CD, CDV, CE..
nice solid thinkpads and sort of classic, especially when you type on THAT keyboard.. you then see how sloppy current era keyboards really are..
i also have 701C system boards with the MWave chip.. these ARE soldered on..

i DO NOT think the MWave chip isw socketed so any swapping will require de-soldering the chip with little way to know if it will work from 760 series to 755 series..

you would be a far better man than I if you can desolder and re-solder that chip, but if you are dead set on trying, don't kill a good 760 series, get one of my chip containing boards and have at it..
if it works write it up, if it fails.. well, how will you know if the cause is a bad de-solder or resolder job or if the chip itself is kaput..

Thanks! I had forgotten my old username thus could not log in. And the password recovery needed username and my email.. Soo i just made a new one

Ok thought so to..

i found this:

"Options for ThinkPad 755CX

ThinkPad 755CX systems support most of the options that were
announced with the IBM ThinkPad 755CE, 755CSE, and 755CD systems.

In addition, announced today is the IBM ThinkPad DSP Upgrade via
ThinkPad EasyServ. The ThinkPad DSP Upgrade can be obtained through
IBM PC Direct(1) only; to order, call 800-IBM-2YOU (426-2968). This
DSP Upgrade is not customer installable. With this DSP installed,
the built-in speaker, microphone, dial volume control, and RJ11
telephone connector provide the following increase in
feature/function.

The Mwave MDSP2780 operates at up to 60 million operations per second
for integrating audio, games, music, data/fax modem, and telephony
into a DSP. Features and benefits include:

o 44.1KHz MPC-2 16-bit audio with real-time compression
o Simultaneous audio play and record
o Digital audio mixing with up to eight open .WAV sources
o General MIDI-compatible, 32-voice wavetable synthesizer
o Sound Blaster** support
o 14.4 Kbps data/fax modem
o Full-featured telephone

- Answering machine with variable speed message playback and
voice compression
- Hands-free, full-duplex speakerphone

Features set can be enhanced by upgrading the DSP software.
"
Feels like it would be somewhat easy to install as an upgrade. I have two more 760s on the way. One was listed as an 760L but after i bought it i looked at the pictures and it was not an L model but an EL with passive matrix.. The L model has VGA and sound! just what i was looking for.. The other one is an ED and a docking thingy with it.

When i bought the 755CX it had the non PnP bios. When installing win 95 it showed "other devices" an Soundblaster emusomthing and a other "mwave" related device.
But when flashing the latest bios with PnP those two devices disappeared.

My unit dont have a 3.5mm output, only one that looks like line in or something.

Thinking i will be taking the 755 apart just for a lookseee

axur-delmeria wrote:The Mwave chip is soldered, yes, but it's on a small board that plugs to the system board. That's why it's possible to replace the Mwave audio with an ESS 1688 on the 760XD.

However, looking at the HMMs of the 755 and 760 series, their Mwave cards have different FRUs, and seem to have different form factors. But since I've never seen a 755 (I had a 760XD a long time ago), I can't be sure.

Ahaa! I see.. So maybe i could take a dsp card from a other 755 then?

thinking about mwave, the 701C had a really nice song and dance presentation when it would boot up..
as a demonstration of the MWave capabilities, all in about 1995 more or less..
i have not had the time or inclination to see if i could get it running on one of my many 701C's that actually still operate..
i suspect you know the issues IBM had with MWave and how they lost a lawsuit over that DSP chip..