View Single Post
Old 2nd Nov 2021, 1:48 pm   #1
Phantomrose1999
Hexode
 
Phantomrose1999's Avatar
 
Join Date: Mar 2008
Location: Melbourne, Victoria, Australia
Posts: 289
Default Grundig TK27 - Low audio output

Hi All,
Got another one and someone has been in it previously.

The playback output is very low, equal to about 20% of normal at max.

It has had new filter caps installed, 47uf / 400v, x 2 (quote small compared to the original can)

Measured the DC and it was low, 220 volts, so removed the old block rectifier and made a new one using 1Kv 3A diodes as the old block rectifiers do go bad.

Put it all back together, and now the DC measures 242 !! no where near the 260-270v stated in the schematic.

Removed the EL95 and the DC came back to 265v, with all other valves in place.


So either something in the EL95 circuit is pulling way more power or the EL95 is playing up and drawing too much power and pulling down the main DC.

Any suggestions from the resident experts please ? do EL95s go leaky ?
Attached Thumbnails
Click image for larger version

Name:	Missing EL95.jpg
Views:	123
Size:	94.6 KB
ID:	244825   Click image for larger version

Name:	Only Magic eye installed.jpg
Views:	105
Size:	96.7 KB
ID:	244826  
Attached Files
File Type: pdf sch_1.pdf (124.9 KB, 80 views)
File Type: pdf sch_2.pdf (120.7 KB, 73 views)
Phantomrose1999 is offline