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Philips210 · 10th Feb 2018, 12:14 am

Hi.

I agree, it's incredible that the set survived after the mains was applied to the 12V input.
I liked the Thorn 1590/1 series and found them to be generally reliable. The usual Thorn cracked solder on the bar of the tuner was a common trouble spot. The LT regulator could cause hum problems due to being leaky. There were a number of production changes over the years including a change to silicon LT regulator and line output transistors which improved the reliability.
Early models had an EHT smoothing capacitor.
I remember one or two problems in the IF stages, sometimes due to transistors and other instability issues due to disc ceramic capacitors. The tubes lasted well and the LOPT was good though not above suspicion.
Miscellaneous troubles included iffy preset resistors and some carbon composition resistors going high.
I have a Ferguson badged 1590 in the loft which I hope to look at before long.

Regards
Symon.

10th Feb 2018, 12:14 am	#6
Philips210 Nonode Join Date: May 2007 Location: Redruth, Cornwall, UK. Posts: 2,573	Re: Marconi 4816 1590 survivor! Hi. I agree, it's incredible that the set survived after the mains was applied to the 12V input. I liked the Thorn 1590/1 series and found them to be generally reliable. The usual Thorn cracked solder on the bar of the tuner was a common trouble spot. The LT regulator could cause hum problems due to being leaky. There were a number of production changes over the years including a change to silicon LT regulator and line output transistors which improved the reliability. Early models had an EHT smoothing capacitor. I remember one or two problems in the IF stages, sometimes due to transistors and other instability issues due to disc ceramic capacitors. The tubes lasted well and the LOPT was good though not above suspicion. Miscellaneous troubles included iffy preset resistors and some carbon composition resistors going high. I have a Ferguson badged 1590 in the loft which I hope to look at before long. Regards Symon.