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Old 2nd Dec 2020, 12:40 pm   #1
stevehertz
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Default Armstrong 600 series tuners and receivers

On Armstrong 600 series tuners and receivers the upper indicator is used for (quote from Armstrong): Preset tuning scale: indicates position of selected stations. For easy setting up of your choice of pre-set stations.

On my unit, as you tune from the lower end of the tuning dial scale (88MHz) to the top end (108MHz) the indicator’s pointer does indeed move from left to right as you would expect, tracking the dial scale, but at about a third of the way it stops. I have monitored the voltage to the indicator and although it does increase linearly for the full dial scale travel, as I say, the indicator itself stops at about a third of its travel. The indicator has an opaque ‘window’ and it looks as if there’s a mechanical ‘stop’ that is stopping the pointer from travelling any further?

Can someone with a working version please tell me how their’s performs? What it should be doing? I’m perplexed at the apparent mechanical stop. I have gotten into similar hifi meters in the past and I may have to on this one, but it’s not easy and a breakage may result.
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Old 2nd Dec 2020, 2:48 pm   #2
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Default Re: Armstrong 600 series tuners and receivers

You might do well to drop a line to Jim Lesurf, who was involved in the design of this series and is still active.
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Old 2nd Dec 2020, 3:25 pm   #3
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Default Re: Armstrong 600 series tuners and receivers

With much care I managed to dismantle the indicator. What appeared to be a nylon 'stop' when viewed through the opaque housing panel was in fact another part of the housing that had melted with the heat of the internal incandescent bulb, and drooped to form a point. Actually, in the photo that 'point' was bigger than what you see but I'd snipped it off before deciding to take a photo. But it was worse, the whole area had drooped and was fouling the needle. So I carefully cut it away and replaced it with some black duct tape. How long that will fair in the heat I don't, whatever, I may have to go in again and/or use LEDs. Anyway, the indicator now tracks the dial scale when tuning (doesn't serve much purpose!*) and although the beginning and end points coincide movement wise, the middle section is quite un-linear. That's just how it must be. Apart from anything else the tuner's dial scale is far from linear.

The other meter is the centre zero tuning one and it reads O/C. Again I've dismantled it to look for a break somewhere, but nothing can be seen. I'll have to see if I can get a replacement.

* One is supposed to gain some useful information about the station frequency when choosing a pre-set station from the indicator showing say '1.5'.
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Old 2nd Dec 2020, 3:30 pm   #4
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Default Re: Armstrong 600 series tuners and receivers

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You might do well to drop a line to Jim Lesurf, who was involved in the design of this series and is still active.
Hi Ted, in reading about the 600 series I've come across his name a few times including an online restoration article by him where he shipped his 626 out to London Sound for a full refurb. Some nice reminisces from him there too.
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Old 3rd Dec 2020, 8:14 pm   #5
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Default Re: Armstrong 600 series tuners and receivers

The two indicators on these seem to be unreliable. I have a receiver and a separate tuner and only one out of the four meters between them works, and that is intermittent I doubt whether replacements can be found.

The 600 series was dogged by unreliability when new. I saved up for the amp as a teenager and proudly went to Hardman Radio in Liverpool with the cash to buy one. They told me that they had so many problems with them that their stock had been returned to Armstrong. I bought a Rotel RX400A for the same price as the Armstrong amp. The two survivors that I own sound great after some restoration, better than the Rotel I think.
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Old 3rd Dec 2020, 8:30 pm   #6
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Default Re: Armstrong 600 series tuners and receivers

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The two indicators on these seem to be unreliable. I have a receiver and a separate tuner and only one out of the four meters between them works, and that is intermittent I doubt whether replacements can be found.

The 600 series was dogged by unreliability when new. I saved up for the amp as a teenager and proudly went to Hardman Radio in Liverpool with the cash to buy one. They told me that they had so many problems with them that their stock had been returned to Armstrong. I bought a Rotel RX400A for the same price as the Armstrong amp. The two survivors that I own sound great after some restoration, better than the Rotel I think.
Indeed Paul, nerd as I am I've recently read a lot about the 600 series and it doesn't always make good reading. There we so many issues with the early ones as you say, and the ones about today often reflect that with numerous issues and problems. For one thing I think they tried to cram too much into a slimline design. The meters were bad, the big electrolytics were poor quality (I have same age Japanese receivers with ones that are good), the tuning dial scale and action is kinda crude and difficult to see, and the knobs are for fairy fingers. Saying all that, looks wise they do have certain charm. I will plod on doggedly with mine and hopefully complete the restoration to full working level.
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Old 3rd Dec 2020, 11:35 pm   #7
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Default Re: Armstrong 600 series tuners and receivers

Basically I think they were a victim of the general poor build quality that was so prevalent in British industry at the time. Cheap components and some poor physical design spoiled what could have been an excellent product. I use mine daily and they sound good. I suppose I shouldn't complain about the maintenance they need so long after the end of their design life
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Old 4th Dec 2020, 9:45 am   #8
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Default Re: Armstrong 600 series tuners and receivers

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Basically I think they were a victim of the general poor build quality that was so prevalent in British industry at the time. Cheap components and some poor physical design spoiled what could have been an excellent product. I use mine daily and they sound good. I suppose I shouldn't complain about the maintenance they need so long after the end of their design life
I would agree with that Paul. All put together and working, they are an 'attractive', dinky looking set. I've ordered the big electrolytics, I am now searching for the centre zero meter or even a scrap donor set. I live in hope.
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Old 4th Dec 2020, 9:54 am   #9
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Default Re: Armstrong 600 series tuners and receivers

I will be very interested to know how you get on with the meter. I also changed the pots that control the quiescent current in mine as the failure of one had blown one of the output transistors. When I put it back together I found that there was a new hum. I traced this to the dressing of the leads that connect the pre amp board to the main one. I changed these to coax and the hum went. I wonder why coax wasn't used in the first place.
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Old 4th Dec 2020, 9:58 am   #10
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Default Re: Armstrong 600 series tuners and receivers

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I will be very interested to know how you get on with the meter. I also changed the pots that control the quiescent current in mine as the failure of one had blown one of the output transistors. When I put it back together I found that there was a new hum. I traced this to the dressing of the leads that connect the pre amp board to the main one. I changed these to coax and the hum went. I wonder why coax wasn't used in the first place.
Again, poor development and design.
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Old 4th Dec 2020, 10:01 am   #11
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Default Re: Armstrong 600 series tuners and receivers

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When I put it back together I found that there was a new hum. I traced this to the dressing of the leads that connect the pre amp board to the main one. I changed these to coax and the hum went. I wonder why coax wasn't used in the first place.
As it didn't hum for the first 50 years it suggests that it was a 'fault' added by you in the way you replaced the leads. Changing to screened leads probably helped reduce the originally non-existent hum.
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Old 4th Dec 2020, 10:45 am   #12
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Default Re: Armstrong 600 series tuners and receivers

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As it didn't hum for the first 50 years it suggests that it was a 'fault' added by you in the way you replaced the leads. Changing to screened leads probably helped reduce the originally non-existent hum.
True but the use of screened leads which were longer than the original ones would have helped with maintenance a lot. The original ones are too short to enable the main amp board to be raised sufficiently to replace components. Again, I am talking many years after the end of the expected life of the unit so my comments are "hindsight" ones really.

I bought both units as not working. The amp had received a lot of ham fisted "maintenance" in the past but the receiver didn't seem to have been worked on at all. The problem with that was that two interconnect leads seemed to have spontaneously disconnected themselves due to poor soldering.
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Old 4th Dec 2020, 12:00 pm   #13
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Default Re: Armstrong 600 series tuners and receivers

I'm getting echoes of the "what rubbish Quad is" thread here...
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Old 4th Dec 2020, 1:24 pm   #14
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Default Re: Armstrong 600 series tuners and receivers

No, it isn't rubbish. A little more attention to detail and a couple more pounds spent on better components would have improved it a lot. I am not qualified to comment on the electronic design, but they sound very good to me.
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Old 4th Dec 2020, 1:24 pm   #15
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Default Re: Armstrong 600 series tuners and receivers

Yeah, let's not go there again.

It's fair to say that the reliability of almost everything has improved significantly since the era of the 600 series (and the 405).

The 600 series were really good looking and a nice change from looking at acres of brushed aluminium panels. THe electronic design was quite reasonable for the period and the cost.

The tuners were interesting being up-converters covering long and medium wave in one swoop. It took guts to do anything different when architectures had sclerosed into only one approach. It's too easy to think "There must be a reason why everybody does it that way" and the reason was the ease of doing IF filters. But newer approaches like ceramic block filters had made that argument a bit dated.

Armstrong might have been precarious around the time, it was their last gasp as a manufacturer.

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Old 4th Dec 2020, 1:47 pm   #16
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Default Re: Armstrong 600 series tuners and receivers

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No, it isn't rubbish. A little more attention to detail and a couple more pounds spent on better components would have improved it a lot. I am not qualified to comment on the electronic design, but they sound very good to me.
I agree with Paul here. It has the basis of nice, great looking - and when working - decent performing set. If they'd made it a bit bigger, used better components and left out a few questionable design features it would be very good. It just failed at the final hurdle - both when new and throughout the years. Cos, that's not to stop the modern day restorer eliminating those faux pas and ending up with a nice working set. I like mine, but as part of the process of discussion I am obliged to mention both good and bad points. Whatever is so wrong with that?! are we only able to speak less kindly of Japanese receivers?
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Old 4th Dec 2020, 4:21 pm   #17
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Default Re: Armstrong 600 series tuners and receivers

The Japanese amps and receivers haven't been bad on the whole. There have been some rather good ones, and some with disappointing aspects, but I don't see any correlation between goodness/badness and nationality.

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Old 4th Dec 2020, 4:36 pm   #18
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Default Re: Armstrong 600 series tuners and receivers

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The Japanese amps and receivers haven't been bad on the whole. There have been some rather good ones, and some with disappointing aspects, but I don't see any correlation between goodness/badness and nationality.

David
Neither do I David, so why the kind of 'question' regarding the Quad thread and now this, an Armstrong 600 series one? People are simply, as has been the case on this forum since it began, discussing their findings and airing their thoughts, impartiality being a given. I like my Quad stuff, I like my Armstrong receiver, I like my Japanese stuff, surely that doesn't stop people talking with hindsight about poor design issues ?
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Old 4th Dec 2020, 4:56 pm   #19
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Default Re: Armstrong 600 series tuners and receivers

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Armstrong might have been precarious around the time, it was their last gasp as a manufacturer.
The 600 series sold well for several years - I think in the end they were outflanked by the flat-earth tendency, whose darling they never were. Those in charge pulled the plug when the 700 series was barely launched, deciding that the land was worth more than the business.
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Old 4th Dec 2020, 7:21 pm   #20
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Default Re: Armstrong 600 series tuners and receivers

I was in the trade 20 years plus
I sold 600 units and in fact could not get enough of them they were on allocation we would order a no of units and would be told what we could have No better or worse than other British gear
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