Teardown: Rigol DM3058 (Multimeter)

[olsenn]

Here are some photos of the insides of a Rigol DM3058 bench top multimeter:









Notice those JTAG headers for the various Altera Max II CPLD's; those could come in handy some day. If anyone has photos of the DM3068 or any other Rigol DMM model, I would love to compare the two... if they're identical as the DS1052E and DS1102E are, then perhaps it can be converted to the higher end version by simply changing the serial number.

I was surprised to see that the numerous LM78XX voltage regulators were all mounted to beefy heat sinks ; is that normal? I've never noticed any problems with heat dissipation in them.

[alm]

Thanks for the pics. Too bad resolution is too low to read markings. You can clearly see the separation between the grounded and floating part of the circuit. I don't see anything that looks like a heated zener reference, like the standard LM399 you expect to find, at least in 6.5 digit models. Dissipation of linear regulators depends on voltage drop over the regulator and current. Since this meter uses only linear supplies to reduce noise in the circuit, it probably draws a fair amount of power for a TO-220.

My guess is that the DM3068 uses at least a different voltage reference (maybe selected, like all the big boys do), and maybe different ADC circuit. I wouldn't count on a DS1052E-style hack. Also the community of Rigol bench meter owners is a lot smaller. Plus calibration is much more critical.

[saturation]

Thanks!  I wish the photos were larger so the labels can be read.  But at minimum its clear the PCB have big Rigol labels on them so I presume its designed by them and the have some control on quality.

[olsenn]

Here's a higher resolution version of one of the photos. The resistor divider is a Caddock 1776.

[ted572]

DM3058 Digital Multimeter Service Guide
http://gotroot.ca/rigol/service%20manuals/DM3058_ServiceGuide_EN.pdf