UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - S2055N horizontal deflection transistor keeps failing on CRT TV with the F19 chassis

Heatercathodeshort · 10th Oct 2017, 6:51 am

The third harmonic tuning capacitor is VERY critical and must be replaced by a special component designed for this circuit position.

Failure to address this will result in high EHT, destroyed line output transistors, CRT flash over causing failure of the CRT, frame output I/C [at least] and other faults.

The original A823 RBM colour chassis originally employed polystyrene types but these soon failed [weeks] and were replaced by special capacitors manufactured by Plessey and marked 16kc/s. I was surprised at the time that a company such as RBM could make such a mistake. You must use the EXACT values. You do not get a second chance with transistor line output stages. John

10th Oct 2017, 6:51 am	#37
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: S2055N horizontal deflection transistor keeps failing on CRT TV with the F19 chas The third harmonic tuning capacitor is VERY critical and must be replaced by a special component designed for this circuit position. Failure to address this will result in high EHT, destroyed line output transistors, CRT flash over causing failure of the CRT, frame output I/C [at least] and other faults. The original A823 RBM colour chassis originally employed polystyrene types but these soon failed [weeks] and were replaced by special capacitors manufactured by Plessey and marked 16kc/s. I was surprised at the time that a company such as RBM could make such a mistake. You must use the EXACT values. You do not get a second chance with transistor line output stages. John