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eHam Forums => Amplifiers => Topic started by: K2ACB on January 05, 2012, 04:16:15 PM



Title: What Does UB mean on the Front Panel of a Solid State Amp
Post by: K2ACB on January 05, 2012, 04:16:15 PM
I have had a Tokyo Hy Power HL2KFX solid state aamplifier for over 6 years. The amp Uses 8 MRF150 FET's. It is no longer in production by Tokyo Hy Power.

Until now the amp has been trouble free. All of a sudden I was using the amp yesterday when a red led on the front panel of the amp went on. Under the led it said UB. That had never occurred before. When that occurred the amp also stopped functioning. The amp still lit up but there was no output.

I immediately took out the manual. It said UB means unbalanced and the amp probably will need repair.


I would like to know what they mean by unbalanced.The manual said nothing more about this.  Could this be a major repair? Could this mean one or more of the FET's went bad?Could it be in the power supply or transformer?

If anybody has any comments I would appreciate it.

73
Alan-K2ACB


Title: RE: What Does UB mean on the Front Panel of a Solid State Amp
Post by: M0HCN on January 05, 2012, 05:46:01 PM
It means that the power combiner is seeing unequal output from the PA blocks, one of them has gone faulty or is not getting power or drive.
It could be power, it could be bias, it could be a blown FET or two.

Could be minor, is likely to be pretty major.

Regards, Dan.


Title: RE: What Does UB mean on the Front Panel of a Solid State Amp
Post by: VE1IDX on January 05, 2012, 07:38:38 PM
UB = Uber-Blown  ::)

The previous poster is correct. The combiner is seeing an unbalance caused by unequal power output from the modules for a variety of reasons. It may be minor but usually isn't.


Title: RE: What Does UB mean on the Front Panel of a Solid State Amp
Post by: TANAKASAN on January 08, 2012, 03:14:16 AM
It should be possible to get this amp working again. Even though only one FET may be blown you will probably find that the amplifier is configured to use four pairs, and so it will be better to purchase and fit a pair of MRF150 devices to the affected module.

Tanakasan


Title: RE: What Does UB mean on the Front Panel of a Solid State Amp
Post by: K7KBN on January 08, 2012, 10:32:26 AM
Stands for "Uuuu... [pronounced OOOoooh]...Boy  This is gonna be expensive!"