Using a DBT and variac on SS equipment ?

[racfan9]

Just curious, Are the same standards in place when using a DBT and Variac on SS equipment? I've always use these items for tube equipment which is usually what I tinker with, but unfortunately my go to receiver which happens to be a solid state Sanyo has lost a channel. Anyway I guess i'll see if I can repair it.

Thanks,
racfan9

 

[whoaru99]

If it is all old school.

Newer stuff with microprocessors and stuff with "trick" power supplies may not work properly enough on the lower voltages to facilitate effective troubleshooting that way.

 

[slimecity]

Yup - generally the only older gear where you don't want to use a DBT/variac on is any amplifier with VFETs in it - but these are fairly uncommon and you will know when you have a piece of VFET gear.

 

[ConradH]

Watch out with Carver mag field amps. I think they cover the use of Variacs in the SM.

 

[fred soop]

I once outsmarted myself using a variac to being up a repaired TV. Many TVs during the 80s and 90s had a horizontal output stage directly connected to the AC line and the rest of the circuit was driven from the horizontal flyback transformer and further isolated with a horizontal input transformer. These will not start with a variac or even an isolation transformer if the current rating is not excessive. It has to be hit HARD with AC to get a large enough jolt out of the horizontal output to kick start the horizontal oscillator. Don't know how many audio devices might have a similar issue.

 

[petehall347]

I once outsmarted myself using a variac to being up a repaired TV. Many TVs during the 80s and 90s had a horizontal output stage directly connected to the AC line and the rest of the circuit was driven from the horizontal flyback transformer and further isolated with a horizontal input transformer. These will not start with a variac or even an isolation transformer if the current rating is not excessive. It has to be hit HARD with AC to get a large enough jolt out of the horizontal output to kick start the horizontal oscillator. Don't know how many audio devices might have a similar issue.

not any i have heard of .. i never had dbt or variac when i played with crt tv.s ..just plugged them in one finger in the ear facing the set . . was often the HOT transistor fix for me .