Mikey 405's BRC 1500

[Studio263]

I collected a 1500 for Mikey 405 yesterday, that's all I had to do, collect it and sit on it unitl someone comes down here to get it... I've not seen a 1500 for ages, so what harm could it do to try it? To my great surprise something happened, though the following faults were noted:
1) no sound
2) IF instability
3) severe lack of height
The IF problem was due to C12 (100uF) being open circuit. For the sound, R96 (2K2) was open circuit and C61 (4uF) was in a bad way, these are in the HT supply to the output stage. The frame was trickier, I started by changing the PCL805 cathode decoupling capacitor C79 (160uF, a 220 went in). Though the capacitor was useless a new one didn't change things much. Both R97 and R100 (both 470K) in the coupling and feedback networks had gone up to 700K but new ones didn't make that much difference either. In the end it turned out that the boost supply to the height control was low because R123 (330K) was now about 700K and C89 (1uF 350V) was leaky. Full height and a reasonably linear scan were then restored.
The last thing to do was to change C84 (100nF) for a proper "x" rated one before there was a big bang and foil everywhere...
The set has its original Mazda CME 2013 tube which to my surprise is still very good.

[Hunts smoothing bomb]

A pic or two maybe?

[BGmidsUK]

I saw that one on sale, would have been interested myself if it was a bit closer! I recognized it as a 1500 straight away, brings back happy memories of the one I rescued for a £ and fixed, which served me well for a number of years mine was the plastic cased HMV version though.


Would love to see some pics



BG

[Nickthedentist]

Very nice to see that the "forum courier service" sometimes provides en-route repairs too

[Studio263]

Originally Posted by Nickthedentist

Very nice to see that the "forum courier service" sometimes provides en-route repairs too.

I wouldn't get too carried away with that idea, I'm not going to be duped into picking up HMV 1807s, Sony KV-1810UBs and Philips N1500s on a similar basis!

Pictures to follow, though I'm sure you all already know what a 1500 looks like. Hold on, one with a decent tube in it may be another matter!

[Lloyd 1985]

I have the Alba badged version (T1520) it had the bad frame cramp which was down to c79, and also there was no picture or sound, which I found was a lack of the 12v going to the tuner. I traced that back to r78 measuring something daft like 10m ohms.. the focus was unadjustabe too, which was r120 gone high. with all that done it gives a brilliant picture!! the crt is labeled 'supervision' possible its a replacement?! either way, i'm dead chuffed with it!! my first 'propper' valve telly restoration!

heres some before and after shots of it..

[Mikey405]

I posted a message up here earlier saying how this was above and beyond the call of duty, but it seems to have been deleted (or it has otherwise disappeared) for some peculiar reason. Anyway, thank you very much Tim, that was most kind. All I need now is to get it out of your way.

PS. That looks like a nice set you have there too Lloyd. Yours has a half-reasonable tube as well.

[Studio263]

Here you go, all that work to watch grown men playing bat and ball...

[Tazman1966]

Looks good Mike and Tim! Is it a 20" or a 24"?

[paulsherwin]

Originally Posted by Mikey405

I posted a message up here earlier saying how this was above and beyond the call of duty, but it seems to have been deleted (or it has otherwise disappeared) for some peculiar reason.

Nothing deleted by mods in this thread.

Paul

[Mikey405]

Originally Posted by paulsherwin

Nothing deleted by mods in this thread.

Paul

Oh well, perhaps it was my browser, or perhaps just my brain not in gear...

[Dave Moll]

Originally Posted by Mikey405

I posted a message up here earlier saying how this was above and beyond the call of duty...

Were you thinking of this one?

[Mikey405]

No, that was one I posted a bit later Dave. It's really no problem - it may be that my browser or Internet Connection was busy and I surfed away from the page before the message had arrived at its destination. Whatever it was, I'm really not worried about it.

[Studio263]

Originally Posted by Tazman1966

Looks good Mike and Tim! Is it a 20" or a 24"?

It's a 20" one, perhaps I should have given the "proper" tube number earlier (AW51-120WR). It's got a lot of emission for a British made Mazda tube.

The teak cabinet looks new after a wipe over with oil (normally reserved for B&O sets) but you can cut down as many trees as you like, the natural home for the 1500 chassis is still a cheap plastic cabinet.

"HMV - put snobbery first"

[dave walsh]

Mikey. must be just a technical glitch but if it's any help I actually saw the missing message you referred to. No need for a conspiracy theory but I understand the "is it my brain" concept. Definetely not but I'm sure Paul [Sherwin] is correct as well. These things just sem to happen sometimes.

Cheers Dave W

[paulsherwin]

Originally Posted by dave walsh

No need for a conspiracy theory but I understand the "is it my brain" concept. Definetely not but I'm sure Paul [Sherwin] is correct as well. These things just sem to happen sometimes.

Mods can see all deleted posts, regardless of who deleted them. There are no deleted posts in this thread.

No more discussion of this subject in this thread please.

Paul

[slidertogrid]

Nice to see a HMV version, most of the ones I saw were in very cheap flimsy plastic cabinets with a wood grain finish printed on, I seem to remember having to be careful with the foam cleaner or it wiped off
Well done for getting it working, as you say a very good tube for a Mazda!
I remember one fault that was a bit nasty, there is a section of the dropper which I seem to remember was a fairly high value (1k or so ), when this goes o/c the L.T supply to the I.F transistors goes high and most of them pop their clogs.
I really liked the 1500, not many common faults. The tuner bar sometimes fell off and there was a 470k (or was it a 47k) that went high causing no sync, the odd valve and tripler, happy days!
Rich.

[Studio263]

Originally Posted by slidertogrid

I remember one fault that was a bit nasty, there is a section of the dropper which I seem to remember was a fairly high value (1k or so ), when this goes o/c the L.T supply to the I.F transistors goes high and most of them pop their clogs.
I really liked the 1500, not many common faults. The tuner bar sometimes fell off and there was a 470k (or was it a 47k)...

That's the 317R section at the end next to the line output valves, as you say it pops off the BF transistors when it goes.

The resistor in the sync circuit is the upper one of the two that feed the anode of the sync seperator (30FL1? pentode section). The diagram shows it as 22K but you often see 47K there fitted from new, I don't suppose it mattered much.