ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Picked up a 1700 yesterday at an estate sale and it has a couple of problems I need advice on please. One of the RCA connectors is damaged, animal chewed through one channel. The second channel emits a loud hum through the phono input of an older receiver. The cartridge is an MM 20E.
Before I attempt to repair the RCA connection I’d like to know if the other ends of RCA cable is simply other RCA’s or will I need to create or replace another connection inside? I have a repair manual that doesn’t appear to show the cable at all.
I’m new to anything B&O and the MMC world. Is it true any device with phono input should function with a MMC cartridge or does the signal need a step up amp?
Thanks, love to resurrect this thing, looking forward to responses.
(if there is a better area of this forum to address these questions, please direct me)
RCA plugs (cable) is not standard for Beogram 1700. It should have a cable ending in a 5-pin male DIN.This DIN plug will have both the signal ground and the chassis ground that are both necessary to keep hum away.If the Beogram was modified to RCA plugs it should also have an extra grounding wire that you should connect to your amplifiers metal chassis, typically a small fingerscrew near the turntable input socket.
Martin
Thanks, there is a black ground wire also. So, is it possible this was a hack job by previous owner that never worked before ? There is no one to ask since the previous owner has passed.
It's possible.It certainly isn't original.
If it's still humming despite mounting the extra ground lead to your amplifiers chassis, it may not have been fitted the right place inside the Beogram.
I removed the bottom plate and see the 5 tangled tiny copper wires soldered each to one of 3 lugs with two to a common and one to the black ground wire terminal. One lug has a red wire soldered, next has a white wire, the two neutrals are twisted together and soldered to the 3rd lug.
Continuity is good everywhere.
The tiny gauge copper wires go through the base into the tone arm. All the copper wires are touching each other which seems to be the design but odd to me.
ill try to post a picture or look for a similar one online a a reality check.
Sounds right.The thin strands are insulated with lacquer.The chassis ground lead should be connected to the metal chassis of the Beogram. Typically right next to the other leads that are soldered totags on the muting switch.
So, the cable makes good solder connections, I test soldered RCA jacks to the damaged ends and tested good continuity. All I get is a loud hum, a lot louder than a buzz on the phono input or an Aux input two different amps. The cartridge and stylus are intact but something is wrong. Simple circuit, maybe the cartridge is bad. Hope not.
I test played a record and can hear a faint bit of music so I know the stylus is tracking.
I guess I should be more clear, there is no sound output at all, either through phono or aux inputs. That’s my real problem.