Its a Marshall JCM 2000 DSL 201, I have just replaced the power valves and need to know how to bias it. There is nothing specific to this amp on the internet. So far I have found PR1 which looks like a pot, CON5 which is a 3 pin connector and set my voltmeter to 200 milivolts DC. Also I have the amp on standby and plugged into the speaker. http://imgur.com/lC2zMPi Thanks