Hi All... I am new to the group and hope someone may be able to help. I have an early Rane SM26 on my bench and in need of a schematic. This unit does not use 7815 type voltage regulators but does have the power supply integral to the unit. Since Rane was bought out (by In Music Brands I think) information has been a bit more difficult to obtain. There is a later SM26 posted on their website but it is newer than the one I have, If anyone has a schematic I would greatly appreciate a copy. Thanks
Comments
If you are talking about an early SM26 rather than the later var
If you are talking about an early SM26 rather than the later variants (SM26S etc), then my understanding is that they all used 50/60Hz mains transformers and 7815/7915s or equivalents for their positive and negative power rail regulators. There have been many different product numbers from the various different semiconductor manufacturers for essentially the same 78/79 series parts, although the pinouts were not always identical. What parts do you have fitted in your unit? I'm assuming from the way your post is phrased that it's the regulators that are giving trouble.
Rane oldman
http://www.rane.com…
Kurt Foster, post: 452167, member: 7836 wrote: http://www.rane.c
Yes, that's the schematic I found for the original SM26 unit, but it shows 7815/7915 regulators that the OP says his unit does not have. I'm intrigued to know what the regulators are in his box.
Boswell, post: 452166, member: 29034 wrote: If you are talking a
thanks for your reply... no as my original post was meant to convey this unit did not use the 78/79 series regulators thus my query.
OK, interesting. What does it use in the way of regulators?
OK, interesting. What does it use in the way of regulators?
It does not.. hence my desire for a roadmap...
It does not.. hence my desire for a roadmap...
The older models used a mains-frequency transformer and linear r
The older models used a mains-frequency transformer and linear regulators. The later versions used off-line switching techniques employing high-frequency transformers with feedback regulation. If your unit does not appear to have lin-regs, perhaps it's one of the later DOLS ones.
What does the transformer look like?
attached is a photo Attached files
attached is a photo
Your photo seems to show a version of the unit that has unregula
Your photo seems to show a version of the unit that has unregulated power rails. If it is indeed an SM26, it may be some sort of early prototype, as I have never seen production Rane gear where the 120/240V mains arrives via an uninsulated fuse on the main PCB, and the power on/off switch is not in the mains circuit but on the low voltage transformer secondary. Those sorts of things have been a no-no for many years except where the power supply is an external enclosed brick.
I can't tell from the angle of your photo, so could you confirm that the vertical piece of metal screen behind the master output level control is just a tinplate screen and does not have any components bolted to the front of it?
It appears to be a shield and there are no components attached.
It appears to be a shield and there are no components attached.
OK, thanks. Sometimes magnetic field screens are made to double
OK, thanks. Sometimes magnetic field screens are made to double up as heatsinks for regulators or power transistors.
My other comments about unregulated rails still stand.
It doesn't appear that this was a prototype as it has a s/n....
It doesn't appear that this was a prototype as it has a s/n.... but again no actual regulation. The op amps appear to function at a +/- 18 volts
Know this is old but figured…
In reply to Know this is old but figured… by scott2000
Nevermind on the led . Just…
In reply to Know this is old but figured… by scott2000
scott2000 wrote: Know this…
Hi, where did you find this schematic? I have the same unregulated SM26 and cant find one.