HELP: how to disassembly '94 512 TR instrument cluster?

The 512TR has an electronic speedo head and is not driven by a cable - it gets an electrical signal from a pulse generater on the gearbox.

 

Can anyone confirm (from the IP address?) if this question is really coming from Brazil?

Seems like an "untrustworthy" first post aimed more at finding out how to make a "512TR mileage adjustment" rather than a repair.

Leopoldo -- I apologize beforehand if your request is legitimate (and I will help in any way I can if so), but your information is so sketchy, and IME disassembling an interior is a big decision -- it's a difficult, time-consuming task and the parts don't take disassembly-reassembly well so the mechanic shouldn't be reaching this conclusion unless he's made the electrical measurements that positively prove it's the speedometer or the local wiring under the dash that needs repair (and, if the problem is located under the dash, how could he know what parts to buy beforehand?).
Please provide more information.

 

Do you know what part was sent? -- (if no diagnostic measurements at all were made) the logical one would be the pulse generator that Malcolm mentioned (but it's installed at the gearbox, and not in the interior, as he mentioned). If the pulse generator is replaced, and the speedometer is still not working, there will be some connectors in the area of the steering column where the mechanic could look for the presence/absence of the signal from the pulse generator (when the diff pinion shaft is rotating) on its way to the speedometer. If the pulse signal is present (but the speedometer still bad) only then would you conclude that the speedometer itself has a problem and needs to come out for repair or replacement (but let's hope your friend won't need to go there ). I don't have a 512TR wiring diagram to be more specific about which connector/wire would be measured for the pulse signal at the steering column, but hopefully it's just the pulse generator.