Hacker Mayflower RV20 - UK Vintage Radio Repair and Restoration Discussion Forum

BBCmicro · 5th May 2023, 7:19 pm

This was is my first go at a valve set and was a little nervous.
I paid too much for it but, it was local and I couldn't say no.

I don't know what the varnish is on these sets but it was extremely resistant to attempts to remove it (third pic as received, finish was cracked, peeling and missing in places, and someone had had a go at the front panel and torn up the grain in the veneer).

A sand down and stain and a few coats of spray varnish got it looking serviceable, it'll never be perfect but it's not bad.

Suffered from a few resistors that went high when the set heated up and would cause increasing distortion until the thing was unintelligible. Worked out which ones by observing where the wax coating was running off, and by burning my finger (set powered off of course!)

Canned caps restuffed (again a first for me) after one leaked everywhere.

Electrolytics replaced and the selenium rectifier emptied and stuffed with silicon diodes.

I haven't the skill or equipment to do an alignment but it sounds fab as is. I will probably need to check resistors around magic eye as the bars do not meet in the middle.

It's rapidly usurping my Roberts R707 as my favourite radio. Hopefully it'll last, but it's got a new lease of life with me for a bit at least.

stevehertz · 5th May 2023, 8:06 pm

Looks nice, great job you've done there. A couple of points from me. You may not get the bars on the signal strength indicator to meet in the middle, it could just be signal level, not necessarily out of tolerance components. On my set I found the sound lacked bass, and I'm not the first person to comment on this. In this thread I describe a non invasive mod that greatly improves the frequency response of the RV20. https://www.vintage-radio.net/forum/...d.php?t=110877

BBCmicro · 6th May 2023, 1:26 pm

Thank you for the tip!
I've ordered a long reach phono plug, when it arrives I'll give it a go.
It's a shame there aren't separate treble/bass controls on this but it does keep operation nice and simple!

stevehertz · 6th May 2023, 5:23 pm

Quote:

Originally Posted by BBCmicro

Thank you for the tip!
I've ordered a long reach phono plug, when it arrives I'll give it a go.
It's a shame there aren't separate treble/bass controls on this but it does keep operation nice and simple!

Well with the mod you only have to adjust for the amount of treble you want. Without it you're wrestling with a sound that lacks bass, so you tend to reduce the treble, but then it becomes muffled. The mod sorts it.

Uncle Bulgaria · 6th May 2023, 7:13 pm

It looks good! Well done.

It may have been on DIY Audio as I can't find a thread on here, but I recall having a lot of help when I was restoring my Mayflower II (also my first restoration) which resulted in the magic eye becoming much more responsive. It is a wonderful sounding radio.

I shall certainly add your mod to my list of things to investigate, stevehertz...

60 oldjohn · 6th May 2023, 8:49 pm

Quote:

Originally Posted by BBCmicro

I haven't the skill or equipment to do an alignment but it sounds fab as is. I will probably need to check resistors around magic eye as the bars do not meet in the middle.

.

That sounds OK to me, the Bars should only meet in middle of the viewing window when stood directly in front centre of the set, if not IIRC the tube can be slid a millimetre or so either way. BTW my experience is with the RV14 but I think they are the same in that respect.

John.

vinrads · 7th May 2023, 9:32 am

First class job well done .Mick.

Pilot Mariner · 10th May 2023, 12:01 pm

Steves tone modification made a such a vast improvement to the sound quality that I made it permanent in all my 3 HM2s.

Post 42 of this thread shows how I incorporated the 2 resistor/1 capacitor arrangement.

https://www.vintage-radio.net/forum/...=179104&page=3

Mark

stevehertz · 10th May 2023, 12:14 pm

Quote:

Originally Posted by 60 oldjohn

Quote:

Originally Posted by BBCmicro

I haven't the skill or equipment to do an alignment but it sounds fab as is. I will probably need to check resistors around magic eye as the bars do not meet in the middle.

.

That sounds OK to me, the Bars should only meet in middle of the viewing window when stood directly in front centre of the set, if not IIRC the tube can be slid a millimetre or so either way. BTW my experience is with the RV14 but I think they are the same in that respect.

John.

I think you're referring to Parallax Error there John? The OP (as I understand it) is talking about the bars (for some reason) not being driven hard enough to meet in the middle. Different thing.

60 oldjohn · 10th May 2023, 1:05 pm

Quote:

Originally Posted by stevehertz

Quote:

Originally Posted by 60 oldjohn

Quote:

Originally Posted by BBCmicro

I haven't the skill or equipment to do an alignment but it sounds fab as is. I will probably need to check resistors around magic eye as the bars do not meet in the middle.

.

That sounds OK to me, the Bars should only meet in middle of the viewing window when stood directly in front centre of the set, if not IIRC the tube can be slid a millimetre or so either way. BTW my experience is with the RV14 but I think they are the same in that respect.

John.

I think you're referring to Parallax Error there John? The OP (as I understand it) is talking about the bars (for some reason) not being driven hard enough to meet in the middle. Different thing.

My Mistake, In that case I would be checking the high value resistors R19 & R20.

John.

BBCmicro · 11th May 2023, 7:58 pm

I've done the wee modification and the difference is very noticeable, a great improvement thanks!

I am out of 2.2M resistors have put in an order. Thanks all!

5th May 2023, 7:19 pm	#1
BBCmicro Tetrode Join Date: Aug 2006 Location: Dundee, Scotland, UK. Posts: 53	Hacker Mayflower RV20 This was is my first go at a valve set and was a little nervous. I paid too much for it but, it was local and I couldn't say no. I don't know what the varnish is on these sets but it was extremely resistant to attempts to remove it (third pic as received, finish was cracked, peeling and missing in places, and someone had had a go at the front panel and torn up the grain in the veneer). A sand down and stain and a few coats of spray varnish got it looking serviceable, it'll never be perfect but it's not bad. Suffered from a few resistors that went high when the set heated up and would cause increasing distortion until the thing was unintelligible. Worked out which ones by observing where the wax coating was running off, and by burning my finger (set powered off of course!) Canned caps restuffed (again a first for me) after one leaked everywhere. Electrolytics replaced and the selenium rectifier emptied and stuffed with silicon diodes. I haven't the skill or equipment to do an alignment but it sounds fab as is. I will probably need to check resistors around magic eye as the bars do not meet in the middle. It's rapidly usurping my Roberts R707 as my favourite radio. Hopefully it'll last, but it's got a new lease of life with me for a bit at least. Attached Thumbnails

5th May 2023, 8:06 pm	#2
stevehertz Dekatron Join Date: Sep 2011 Location: Rugeley, Staffordshire, UK. Posts: 8,830	Re: Hacker Mayflower RV20 Looks nice, great job you've done there. A couple of points from me. You may not get the bars on the signal strength indicator to meet in the middle, it could just be signal level, not necessarily out of tolerance components. On my set I found the sound lacked bass, and I'm not the first person to comment on this. In this thread I describe a non invasive mod that greatly improves the frequency response of the RV20. https://www.vintage-radio.net/forum/...d.php?t=110877 __________________ A digital radio is the latest thing, but a vintage wireless is forever..

6th May 2023, 1:26 pm	#3
BBCmicro Tetrode Join Date: Aug 2006 Location: Dundee, Scotland, UK. Posts: 53	Re: Hacker Mayflower RV20 Thank you for the tip! I've ordered a long reach phono plug, when it arrives I'll give it a go. It's a shame there aren't separate treble/bass controls on this but it does keep operation nice and simple!

6th May 2023, 7:13 pm	#5
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,333	Re: Hacker Mayflower RV20 It looks good! Well done. It may have been on DIY Audio as I can't find a thread on here, but I recall having a lot of help when I was restoring my Mayflower II (also my first restoration) which resulted in the magic eye becoming much more responsive. It is a wonderful sounding radio. I shall certainly add your mod to my list of things to investigate, stevehertz...

7th May 2023, 9:32 am	#7
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,755	Re: Hacker Mayflower RV20 First class job well done .Mick.

10th May 2023, 12:01 pm	#8
Pilot Mariner Hexode Join Date: Jun 2003 Location: Burntwood, Staffordshire, UK or Kabaty in Warsaw Poland. Posts: 439	Re: Hacker Mayflower RV20 Steves tone modification made a such a vast improvement to the sound quality that I made it permanent in all my 3 HM2s. Post 42 of this thread shows how I incorporated the 2 resistor/1 capacitor arrangement. https://www.vintage-radio.net/forum/...=179104&page=3 Mark

11th May 2023, 7:58 pm	#11
BBCmicro Tetrode Join Date: Aug 2006 Location: Dundee, Scotland, UK. Posts: 53	Re: Hacker Mayflower RV20 I've done the wee modification and the difference is very noticeable, a great improvement thanks! I am out of 2.2M resistors have put in an order. Thanks all!