UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Sony 9-90 Width Control?

Studio263 · 23rd Apr 2018, 9:48 am

The correct way to adjust the width on one of these is to add or remove capacitance across the C-E terminals of the line output transistor. It's mentioned in the full manual (which you can download from Mikey's site) and is a bit of an encumbrance, but that's the method the factory in Japan uses. The same thing applies to all the Sony monochrome sets that I've seen, right up to the end of production.

Note that all Sony sets of this era seem to be rather over-scanned, its just how they are. The TV9-90UB has no power supply regulator, it relies on a delicate balance of power supply output impedance and receiver load. It is therefore unwise to make any alterations to anything in the power supply or damage to things like the line output transistor and the tube heater can result.

23rd Apr 2018, 9:48 am	#19
Studio263 Octode Join Date: Apr 2007 Location: Hampshire, UK. Posts: 1,577	Re: Sony 9-90 Width Control? The correct way to adjust the width on one of these is to add or remove capacitance across the C-E terminals of the line output transistor. It's mentioned in the full manual (which you can download from Mikey's site) and is a bit of an encumbrance, but that's the method the factory in Japan uses. The same thing applies to all the Sony monochrome sets that I've seen, right up to the end of production. Note that all Sony sets of this era seem to be rather over-scanned, its just how they are. The TV9-90UB has no power supply regulator, it relies on a delicate balance of power supply output impedance and receiver load. It is therefore unwise to make any alterations to anything in the power supply or damage to things like the line output transistor and the tube heater can result.