Kasino K200 Issue [message #27603] |
Tue, 03 December 2019 12:24 ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
cejay825
Messages: 5 Registered: December 2019
|
Junior Member |
|
|
Picked up a sickly Kasino 200 awhile back. Replaced the 2 large caps....amp had a hiss that wasn't volume depend. started looking into a few things, DC rail volts are around 7.79v and supply is 40v ...on the pre amp board (PC5013)... I was finding so many resistors out of spec that I replaced most all of them with 1% units, replaced all of the electrolytic caps, also Q5, Q6, Q7, Q8, Q9 and Q10 with 2N4401 and 2N4403 units and Q9 an NTE 326 JFET. The hiss is now gone and the amp sounds great BUT I can't get rid of a small DC voltage on the Selectone, Selective Boost,bright switch, treble and bass pots ( no volts on the volume pot).The voltage varies from .3 to .4 volts depending on where you check. The readings seem good except for two points. Q6 collector should be +.1v but reads +.398v and Q10 collector should read -.2v but reads + 1.25v. My guess is C2 on the power board (PC 5024) is preventing this stray DC from reaching amplification ?. Its driving me crazy, any ideas ?
|
|
|
Re: Kasino K200 Issue [message #27605 is a reply to message #27603] |
Wed, 04 December 2019 06:50 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
stevem
Messages: 4765 Registered: June 2004 Location: NY
|
Senior Member |
|
|
Just because you put in new caps does not mean that they are not somewhat defective and leaky!
I test all of the new caps I get for leakage / ESR.
I would start by replacing C12 again and confirm that it's installed right.
I like to use non polerized electrolytic caps in uncoupling locations like C12.
[Updated on: Wed, 04 December 2019 06:51] Report message to a moderator
|
|
|
|
Re: Kasino K200 Issue [message #27608 is a reply to message #27603] |
Wed, 04 December 2019 12:58 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
chicagobill
Messages: 2005 Registered: April 2003
|
Senior Member |
|
|
How are the controls set on the preamp when you are taking the voltage measurements?
Also, I've seen some cases where the voltages on the schematic are not quite right, so you may be trying to match an impossible number.
|
|
|
|
|
|
|
|
|
|