[volt-nuts] Documentation for 4808/Option 70 Wideband Source

David C. Partridge david.partridge at perdrix.co.uk
Wed Jul 19 07:46:04 EDT 2017

I just received an email which said:

>Every wideband option 70 unit that I have serviced includes an additional board as well as the firmware and the mod to the keyboard to add the WB button. It is added to the main box at the back on the center >metal plate holding the mains transformer. It is installed electrically between the motherboard and the analog connector for option 60/70. The board includes a relay that disconnects the PHI and IHI signals and >what appears to be diode clamp protection, though I have not taken the time to look closely at the rest of the circuit.


-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces at febo.com] On Behalf Of David C. Partridge
Sent: 19 July 2017 09:54
To: 'Discussion of precise voltage measurement'
Subject: [volt-nuts] Documentation for 4808/Option 70 Wideband Source

I've just received the 4808 documentation pack of which I spoke.   I now
have full documentation for the 4808 and the 4600.

Sadly, the only document for the Wideband Source was the schematics.  No User or other manuals were in the package.

Naturally I'm delighted to have even just the schematics, but if anyone knows the whereabouts of the other manuals for the Wideband Source, and could scan them that would excellent.

It's also interesting to note that to fit Option 70 requires an replacement for the EPROM in the 4808 and some tracks to be cut/jumpers added on the keyboard PCB in the 4808.


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