View Single Post
Old 9th Sep 2019, 1:54 pm   #30
DonaldStott's Avatar
Join Date: Aug 2015
Location: Glasgow, UK.
Posts: 1,205
Default Re: Kolster-Brandes MR10

Making steady progress with replacing out of tolerance resistors along with the waxy paper capacitors and Hunts Mouldseals. Replacing one at a time and testing each time just in case something goes wrong but so far so good!

The tone control has had several doses of DeOxit D5 Contact Cleaner but you can only turn it about one third of the way round before the audio breaks up and you get a hum! I'm thinking that there may be mechanical wear issues rather than just needing to clean the internal track and contacts - advice please?

I'm also still struggling with the fact that there is no schematic that matches the components I have in this set. I've already mentioned the replacement of the 7-pin 6BE6 with a 9-pin Mullard ECF82 but there are components in this set not showing in any schematic and similarly there are components missing that are shown in the schematic.

One example is the 47kΩ resistor shown in the middle of the picture below - anyone shed some light on what this is: -

Click image for larger version

Name:	IMG_20190909_132652.jpg
Views:	85
Size:	127.2 KB
ID:	189791

In Post #9 above I mentioned the underside of V2 which is the 9-pin Mullard ECF82 and how busy things were at that location. This next picture shows this in more detail where we have three Hunts Mouldseals and two resistors (22kΩ and 220Ω) but I cant seem to relate these to the schematic?

Click image for larger version

Name:	IMG_20190909_132717.jpg
Views:	71
Size:	90.1 KB
ID:	189792
BVWS Member
DonaldStott is offline