A Little TLC for an Orange Amplification 15 Watt Head

This unit came in to the shop with intermittent signal and power issues. First, we need to get this unit functioning consistently. Only then is it possible to find other issues that need attention. Could The Unbrokenstring Crew have a look at it and bring it back to its full potential?

This all-tube unit looks too new to have any problems at all. Sure enough, it did not power-on as it should. Let’s take a look at this unit before we open it up.

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Many features are packed into this little guy. And I love the color!

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Bringing out the Send and Return functions adds versatility when using effects. And there are plenty of jacks for connecting speaker cabinets.

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The Name/Rank/Serial Number picture helps when ownership changes. The Unbrokenstring Blog has already identified one piece of stolen gear.

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Remove-able IEC line cords are always nice. But how do we set the AC line voltage? I see an ink mark, but no switch.

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When we pull the case off, we are greeted with a pleasant sight of all tubes (and solid state rectifiers under the chassis.)

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Cruising around the sides, we find something of interest!

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Here is the switch to set the AC mains voltage. D’oh!

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Other than the fact that the tube sockets are soldered to the PC board, there is very little to dislike regarding the design and layout of this unit.

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The power supply section appears to be in good condition. The solid state rectifiers are to the left and up from the green PASSED sticker.

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From left to right, we see the ON/OFF switch and the power level setting switch, the pilot light, volume control, and the bass tone control.

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Picking up again from the bass tone control, we see the MID tone control, treble tone control, and the GAIN knob.

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Next to the GAIN control is the input jack. These jacks switch signals when no plug is inserted, so we need to check the operation of all these jack switches once the unit is operational.

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The power fuse looks good, if not a little saggy. We should check it electrically.

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Well, what do you know? This fuse has been storing up a lot of Ohms; in fact, over two million ohms (which is more than my meter will measure.)

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This spade connector has come loose. It could account for this unit not working, as well as the fact that the fuse had open-circuited and begun accumulating all those Ohms…

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These switching jacks are the source of the intermittent audio. They are all cleaned with DeOxIt and cycled several times to renew them.

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After a new fuse and after cleaning the switching jacks and reattaching the loose wire, this unit is 100%.

Thanks for reading all the way to the end!

CONTACT – David Latchaw EE
281-636-8626

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