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Old 19th Jan 2021, 1:03 pm   #21
OldTechFan96
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Thanks for the replies so far!

Extending the legs of modern components with wire or capacitor legs is something that I want to get better at doing. The exposed wire and extension would look good when wholly covered in suitable sheath or thin braid. I have used heat shrink tubing in the past for this. Using braid to cover extensions would give things a period correct look.

When it comes to replacing capacitors I replace them in the order given in the service manual.

J-hooking and soldering onto coils of wire is a really good way of doing things.

Valve sets I've worked on in the past have all been from the 1950's with all glass valves so the short lead length of new components has not been a problem. Usually I would completely remove the leg from the valve holder. Clearing tags can be tricky, but it is doable with a good solder sucker and sharp side cutters.

The need for wanting to develop a better technique came about when working on my Ultra Model 50 where the lead lengths were longer. My under chassis work here looks poor looking back and I would like to redo it all. Some under chassis photos can be found in my Model 50 thread.

Nice work on that chassis Al. Wiring looms are something that I have never thought about before.

A few more things for consideration:

What are the best ways to mount electrolytic capacitors under a chassis?

Strain relief methods for keeping mains leads in place? Lots of manufactures just used a knot, which is not ideal.
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Old 19th Jan 2021, 1:52 pm   #22
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Quote:
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Quote:
Originally Posted by David Simpson View Post
Regarding re-location of components & more neat runs of wiring causing PO in domestic sets - I don't think that designers or factory bench staff considered that as a reason for choosing higgledy - piggledy wiring.
Philips for one, gave instructions in some of their radio receiver service manuals as to the specific placing/orientation of some components.

Lawrence.
Couldn't remember a specific model when I wrote that post but I've now remembered one that serves to illustrate the point I was making, Philips 141U, refer to the manufactures manual:

https://www.service-data.com/product...67/5739/m14567

Note the underneath chassis layout and the orientation of C12 (the AGC de-coupler) in regards to the capacitors outer foil connection (it connects to chassis/ground) and the positioning of the capacitor between the anode leads of the mixer and IF amplifier.

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Old 19th Jan 2021, 2:00 pm   #23
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

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Strain relief methods for keeping mains leads in place? Lots of manufactures just used a knot, which is not ideal.
I use 'P' clips because I have a lot of them.

Grommets are available which grip the flex when they're clamped onto it and pushed into the hole in the chassis.
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Old 19th Jan 2021, 2:10 pm   #24
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Quote:
Originally Posted by OldTechFan96 View Post

Nice work on that chassis Al. Wiring looms are something that I have never thought about before.
Thanks OldTechFan! Much appreciated

A few more things for consideration:

Quote:
Originally Posted by OldTechFan96 View Post
What are the best ways to mount electrolytic capacitors under a chassis?

Especially if you can give them support on at least one side as well as the underneath of the chassis, you can tuck them in as shown in the photo I've uploaded.

I am happy to use a couple of beads of mil. spec silicone, which are out of sight and easily removed if someone wants to in the future. It is a ready source of shock-mounting and very reliable.

(P.S - in this case, the tag strip looks bowed and was in fact broken through some kind of stress when I received the set to restore it. There is also a resistor with one lead disconnected, if you're eagle-eyed!)


Quote:
Originally Posted by OldTechFan96 View Post
Strain relief methods for keeping mains leads in place? Lots of manufactures just used a knot, which is not ideal.
P-clips are good. You can salvage them from scrap equipment. They used to make really nice alu ones, but it's not a thing that's usually being aesthetically evaluated. There are plenty of current suppliers, or maybs put a request in parts wanted.


If you are doing a repair/restoration and you keep putting a strain on the mains lead as you turn over the chassis and test it incrementally, strain relieve the mains cable temporarily with cable tie or two.
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Old 19th Jan 2021, 5:21 pm   #25
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Yep, I fully understand & appreciate that the structural dynamics of certain components need to be considered in relation to say anode & grid circuitry. But in general, I reckon that higgledy-piggledy-ness was just an accepted practice in many mass produced domestic valve radios from the mid 30's through to their post-tranny demise in the 60's.
Another annoying circuitry stumbling block for the un-initiated is heffing "punched out" earth spikes on a chassis. Mostly galvanised steel & hellish reluctant to be de-soldered & unwrapped, due to the chassis itself being one big "heat-sink" in relation to your soldering iron's tip. A simple wee tinned tag might only need 340 - 350 deg. for quick removal of a component, but in many cases another 30 deg. is often required.
For the novice or "new to the game" enthusiast, in the past I've several times recommended a lot of practice on some old gash chassis. Plus learning wire stripping & tinning with gash off-cuts of wire & flex. Before attempting a nice Hacker or Grundig or Eddystone or Ferrograph or B & O, or whatever.

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Old 19th Jan 2021, 5:22 pm   #26
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

My preferred method of anchoring replacement mains-leads is to use a screw-up cable-gland fitted into the hole - this provides good anchoring as well as insulation to protect the cable's sheath against the potentially sharp edges of the hole.

For extra security I'll put a couple of cable-ties on the cable inside from the gland; this makes a really strong attachment - good enough for you to suspend the radio by its mains-lead without risk of the lead pulling-out!
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Old 19th Jan 2021, 5:47 pm   #27
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

P-clips are something I have been wanting for a while. Those glands look quite useful.

'Quality Standards For Assembly' will be a worthwhile read. It is a standards manual for electronics manufacturing.

David Simpson's mention of Eddystone is interesting as I had an 840A which looked almost impossible to work on! Everything was inaccessible.
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Old 19th Jan 2021, 6:17 pm   #28
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

I didn't know what P clips were, but now I do, I can say I have often made them out of strips of plastic.
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Old 19th Jan 2021, 6:34 pm   #29
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

You can get some really-large P-clips - large enough to make a good job of retaining a big under-chassis electrolytic smoothing-capacitor.

The ones I use are made by a company called Hellermann-Tyton.

https://www.hellermanntyton.com/prod...uery=HP-Series
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Old 20th Jan 2021, 12:20 pm   #30
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

CPC do a good range of P-clips which are incredibly cheap in packs of 100 which will do you for a while! Also for more recent items, a selection of cable ties - also very cheap - are invaluable.
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Old 20th Jan 2021, 1:39 pm   #31
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

There is the matter of horses for courses.

If you're doing an HF/VHF/UHF circuit then you really need components as directly mounted as possible. Aesthetics has to go out of the window.

If you're down at comfortable audio, you can afford tag boards and harnesses, rather like Quad and Leak gear of the period.

But watch out. If you're using fast devices at low frequencies, you still have to use the construction styles suited to their frequency capabilities if you want stability.

David
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Old 20th Jan 2021, 3:06 pm   #32
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Parallel lines & stray eddy currents aren't the best of bedfellows, nor too much screening as David, GJ & Lawrence have suggested.

Attached are photos of a creation of mine, made in 2006, been in regular use since, with only the Phono-stage valves upgraded in 2012 (I think). Aside from some labels dropping off, it still sounds very nice, and probably has some 'phoolery in there(!) I'm braced guys ...

Anyway, you may notice the lack of internal cable screening, which in this application caused many a headache, not least due to the lack of space. You can see how small the pre-amplifier is, by the ECC88's poking out the top.

Rather than have many or some earth leads, 'starred' to one spot, it was better noise wise to have a single earth 'bar' but, keep the heater ground to mains ground, PSU & signal decoupled to real ground via a cap. What really kept the noise down was mounting the transformer & mains 'stuff' in a separate enclosure, hence the 7-pin XLR on the back of the pre-amp.

I have another creation, much like this, minus the phono-stage, self-powered, which uses tag-board. If you'd like to see inside, I'll dig it out. From memory, it's construction was better than the item pictured.

Amazing what you can knock-up in an old shed armed with a box of goodies

Point 5 in my previous post was relating to replacement of parts, rather than fault finding. I wasn't sure if you are working on a factory made product or a home creation, where you 'build' your way out of the box. Much like the item pictured ...

I'll grab me coat ...

Mark
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Old 20th Jan 2021, 3:56 pm   #33
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Rather than lacing cableforms, I like to use short lengths of heatshrink sleeving to hold wires 'bundled' - this has the advantage that you can assemble everything, form the cabling into what you consider a neat shape, _then_ waft it with the hairdryer so the heatshrink contracts and retains things in that position.

There's also available some nice slip-over black or grey Nylon tubular braid which can help give a professional appearance - for use with this you can get pre-formed heatshrink "T" and "Y"-junctions for the points where leads need to break-out from the main cableform.

RS sell it as, for example Stock No. 408-215 There's a fibreglass version also available which would be useful where cableforms run near to hot valves.
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Old 20th Jan 2021, 4:06 pm   #34
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

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I have another creation, much like this, minus the phono-stage, self-powered, which uses tag-board. If you'd like to see inside, I'll dig it out. From memory, it's construction was better than the item pictured.
Hi Mark, yep, let's see them please!

That's a classy construction indeed on the photos you've shared - looks very high-end, kudos to ya!
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Old 21st Jan 2021, 3:56 pm   #35
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

The first two photos are of an earlier (silver) pre-amp creation, similar to yesterdays, I'm guessing circa 2003 this time, lower & upper decks (chassis) are solid brass, and what with the mains transformer & choke, it has a reassuring weight to it. This item is one of the easiest home-made projects to service, with its hinged upper deck & 'stay'.

As G6Tanuki has mentioned, using heatshrink is a great idea, which was employed in the the 2nd picture for the signal leads. These are screened & have also been laced. The tagboard is as you'd expect.

Mains power leads can be secured by glands, Heyco compression clamps, or in this case, an I.E.C connector with its power connector retaining clip. P-clips work well too for securing, as others have suggested.

Pictures 3, 4 & 5 are of a recent project, a bluetooth power amplifier which runs off the solar setup in our hobbyroom at the bottom of the garden.

A good example of heatshrink & p-clip usage, plus the braided DC power lead plus some more heatshrink. The main PSU caps have been mounted via chassis-mount/PTFE turrets? tags? The smaller one's on the PCB have been folded over, & sleeved tinned copper wire over the end & soldered, to keep them secure.

Hope these are helpful, I should probably do some writeups in the 'home made' section. I'm sure some would find my 'Blunderbuss' amplifier interesting ...

Thank you Al for your kind words on the silver pre-amp yesterday, I ended up listening to the one pictured here for 3 hours last night ... an enjoyable sound.

Mark
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Old 21st Jan 2021, 5:17 pm   #36
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Anything that encourages folk to carefully secure & identify chassis wiring, such as Mark's excellent examples, is what VR folk should aspire to. Just because dozens of pre & post war domestic radio manufacturers adopted a quick cheapo hig/pig method of wiring, it doesn't mean major refurbishments or homebrew projects, by VR enthusiasts, have to be carried out in the same scruffy manner.
Looming & lacing, P clips, ceramic tag pillars, Hellerman sleeving, H/Sh. sleeving, & so on, can all be achieved, to a high standard, by aspiring enthusiasts. Just needs lots of practice, and maybe some hands-on mentoring once covid restrictions permit.

Regards, David
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Old 25th Jan 2021, 8:44 am   #37
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Here's a brilliant way to lengthen component leads - https://www.diyaudio.com/forums/tube...ml#post6463861

Here's a great way to secure electrolytics - https://www.youtube.com/watch?v=L18g_o0FHSM - https://adapt-a-cap.com/collections/all

When removing components from a tag board, cut em off, trying to unwind component leads from tag's is a nightmare and results in damage. I never wind leads round tags, it's not necessary to get a good joint and it's a nightmare to remove components.

Re securing mains leads,why bother? Fit an IE socket, it's neater and saves having a pesky mains lead snagging whenever you move said item.

For neatness in any circuit get all resistors pointing the same way, EG with gold tolerance band pointing to the left and make sure components are centered on a tagboard. Make wiring as short as possible and neat as poss, lacing bundles or wires together.

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Old 25th Jan 2021, 11:08 am   #38
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

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When removing components from a tag board, cut em off, trying to unwind component leads from tag's is a nightmare and results in damage. I never wind leads round tags, it's not necessary to get a good joint and it's a nightmare to remove components.

Andy.
I agree - I've done that for many years. Trying to needlessly unsolder a faulty component from a a tagboard or valve-holder when other components share the same tag is just asking for trouble, especially on small bases such as B7G, B8A and B9A. Much better to leave 1cm of the old lead still attached and to wind say ten turns of the new component lead around a 0.8mm drill bit, a needle, paper clip or whatever, slip it over the 1cm stub and solder it.

Also useful for extending component leads.

I think Philips used that technique extensively on radios.

Some pics attached.
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Old 25th Jan 2021, 11:15 am   #39
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

Quote:
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Quote:
Originally Posted by Diabolical Artificer View Post

When removing components from a tag board, cut em off, trying to unwind component leads from tag's is a nightmare and results in damage. I never wind leads round tags, it's not necessary to get a good joint and it's a nightmare to remove components.

Andy.
I agree - I've done that for many years. Trying to needlessly unsolder a faulty component from a a tagboard or valve-holder when other components share the same tag is just asking for trouble, especially on small bases such as B7G, B8A and B9A. Much better to leave 1cm of the old lead still attached and to wide say ten turns of the new component lead around a 0.8mm drill bit, a needle, paper clip or whatever, slip it over the 1cm stub and solder it.

Also useful for extending component leads.

I think Philips used that technique extensively on radios.

Some pics attached.
What about advice on lengthening leads on transistors satisfactorily? I seem to be replacing bad af117s a lot and the replacements I use have very short leads.

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Old 25th Jan 2021, 5:58 pm   #40
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Default Re: How To Do a Neat Job With a Point to Point Chassis?

For those who are about to start a new project with an empty chassis, I've been using this excellent free software recently.

DIYLC (do it yourself layout creator) http://diy-fever.com/software/diylc/

I'm currently at the early stages of laying out a point to point build with tag strips, example attached.

Doug
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