orange ad30 htc keeps blowing main fuse, please help

[elooong]

I practiced with my band on my orange on night and it ran fine. The next day when i went to turn on my amp it failed to do so and the light failed to turn on. I checked the fuses and the main fuse was blown. There are two fuses on the amp the main fuse(the one that is blowing) which is a 4amp slow blow 250v fuse, and the ht fuse which is a 500milliamp 250v fuse. The ht fuse is fine. I replaced the main fuse and the light came on when i started the amp. It ran for aproximately 30seconds on standby and the light shut off. It then failed to turn on again, i checked the fuses again and the main fuse was blown. I have been told that my next action should be checking the tubes. Possibly the rectifier.

Is there any way to pinpoint a blown tube without paying for a whole set of new tubes? And if its not the tubes what else could it be. Is there anything i can do myself that has no risk to my amp to help pinpoint the problem? I'm praying its not a transformer. Because its an orange its hard to find someone to work on it. I'm on a deadline to sell the amp but can't until its fixed.

Any advice at all would be extremely helpful :o

[elooong]

bump

[drgonzoguitar]

Unless you have a tube tester, you cannot determine if the tubes are bad. It sounds like you might need a tech, but you could replace the tubes to start with.

[SatelliteAmps]

Probably not tubes. Some other part in the amp is failing. Could be a cap, rectifier, bias supply, etc.

[TopBooster]

Sounds like a shorted rectifier tube to me... Try changing the GZ34 first.

[tlpruitt]

Sounds like a shorted rectifier tube to me... Try changing the GZ34 first.

Ditto. Modern GZ34 rectifiers are notoriously unreliable.