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7m heater   2002-07-09 09:22:00 <Robbi Wright>
Hi,

I don't know how many other people have fixed their heater boxes but if you take the centre console fascia panel off...the rubbery vinyl one, then you will see that the heater control panel box is held in by four screws. If you undo these then you can take the control box out...it has two plugs in the back which need to be undone...

then dismantle it carefully, very easy.....to get to the main circuit board. If you have a spare hour, sit down with a soldering iron and some sold and resolder every joint on the board...then put it all back to gether and if everything has been done right, PRESTO a working unit...

I did this in my supra and it fixed all of my heaters problems....alternatively you may need to do the resistor fix which cully just did to his...

I don't know how to do that one...

cheers,

robbi


-----------------------------------------

Hi guys,
A few years ago , one of my MK111's had a heater problem that started out as intermittent , and then total lack of heat . It was eventually diagnosed (and fixed) by an auto electrician as a dry joint somewhere.......
Now my other MK111 is doing exactly the same thing !
I would be grateful if anybody has any ideas on where to look for the fault.... ( to save another trip to an auto electrician).
Regards
Will Scollay ( known these days a "chilly Willy" )
---
Supra Club of New Zealand
http://www.supras.org.nz/

(html version)
Reply

Re: 7m heater   2002-07-09 23:48:00 <Glen Wolfe>
While heaters / climate control units are on topic ...

I recently had the heater fan fail on the low speeds. Removal and
disassembly showed the commutator worn almost through to the base
plastic (with climate control the fan probably runs as long as the
engine is on I guess). An electric motor rewind shop rewound it for me
with a new commutator (for $A 195) but the speed failure was due to the
series resistance wire breaking. Low fan speed is achieved by placing a
resistance in the current path to the motor - the higher resistance (for
low speed) being a coil of thin wire. Since this needs to get rid of
quite a bit of heat, it is mounted on a plate which projects it into the
air flow made by the fan! ... with a section of ducting lined with a
folded metal formation so the plastic would not melt. A bit like an
incandescent light bulb filament. Well I guess it worked (until it
failed - after 13 years). $2 worth of 10w resistors folded into a shape
to fit the cavity solved that problem - I guess the motor needed the new
commutator anyway ...

Robbi Wright wrote:

> Hi, I don't know how many other people have fixed their heater boxes
> but if you take the centre console fascia panel off...the rubbery
> vinyl one, then you will see that the heater control panel box is held
> in by four screws. If you undo these then you can take the control box
> out...it has two plugs in the back which need to be undone... then
> dismantle it carefully, very easy.....to get to the main circuit
> board. If you have a spare hour, sit down with a soldering iron and
> some sold and resolder every joint on the board...then put it all back
> to gether and if everything has been done right, PRESTO a working
> unit... I did this in my supra and it fixed all of my heaters
> problems....alternatively you may need to do the resistor fix which
> cully just did to his... I don't know how to do that
> one... cheers, robbi ----------------------------------------- Hi
> guys,A few years ago , one of my MK111's had a heater problem that
> started out as intermittent , and then total lack of heat . It was
> eventually diagnosed (and fixed) by an auto electrician as a dry joint
> somewhere.......Now my other MK111 is doing exactly the same thing ! I
> would be grateful if anybody has any ideas on where to look for the
> fault.... ( to save another trip to an auto electrician).RegardsWill
> Scollay ( known these days a "chilly Willy" )---
> Supra Club of New Zealand
> http://www.supras.org.nz/---
> Supra Club of New Zealand
> http://www.supras.org.nz/

--
#################################################################
Dr Glen Wolfe
Software Engineer g.wolfe@computer.org
#################################################################


(html version)
Reply

Re: 7m heater   2002-07-10 09:13:00 <marc.a@...>

Lee D was talking about replacing this resistor pack with an electronic PWM
circuit instead; hows this going Lee?


> with a new commutator (for $A 195) but the speed failure was due to the
> series resistance wire breaking. Low fan speed is achieved by placing a
> resistance in the current path to the motor - the higher resistance
> (for
> low speed) being a coil of thin wire. Since this needs to get rid of
> quite a bit of heat, it is mounted on a plate which projects it into
Reply

Re: 7m heater   2002-07-10 09:41:00 <Lee Dobson>
Should have it in this weekend

As marc said it uses pulsed width modulation to switch the motor on and off
therefore you can use small currents to drive the circuit and do away with
the large ceramic style resistors that always seem to break down

Will keep all informed to its completion

Cheers
Lee

----- Original Message -----
From: <marc.a@paradise.net.nz>
To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
Sent: Wednesday, July 10, 2002 9:12 AM
Subject: [sconz] Re: 7m heater


>
> Lee D was talking about replacing this resistor pack with an electronic
PWM
> circuit instead; hows this going Lee?
>
>
> > with a new commutator (for $A 195) but the speed failure was due to the
> > series resistance wire breaking. Low fan speed is achieved by placing a
> > resistance in the current path to the motor - the higher resistance
> > (for
> > low speed) being a coil of thin wire. Since this needs to get rid of
> > quite a bit of heat, it is mounted on a plate which projects it into
>
> ---
> Supra Club of New Zealand
> http://www.supras.org.nz/
>


Reply

Re: 7m heater   2002-07-10 12:44:00 <Grant Brunton>
Actually, funny that this should be mentioned.......A coupla days ago I noticed the heat from my heater being slightly intermittent. ie heat would be going but would stop for brief periods.

----- Original Message -----
From: Robbi Wright
Sent: Tuesday, 9 July 2002 9:21 a.m.
To: Supra Club of NZ Mailing List
Subject: [sconz] 7m heater

Hi,

I don't know how many other people have fixed their heater boxes but if you take the centre console fascia panel off...the rubbery vinyl one, then you will see that the heater control panel box is held in by four screws. If you undo these then you can take the control box out...it has two plugs in the back which need to be undone...

then dismantle it carefully, very easy.....to get to the main circuit board. If you have a spare hour, sit down with a soldering iron and some sold and resolder every joint on the board...then put it all back to gether and if everything has been done right, PRESTO a working unit...

I did this in my supra and it fixed all of my heaters problems....alternatively you may need to do the resistor fix which cully just did to his...

I don't know how to do that one...

cheers,

robbi


-----------------------------------------

Hi guys,
A few years ago , one of my MK111's had a heater problem that started out as intermittent , and then total lack of heat . It was eventually diagnosed (and fixed) by an auto electrician as a dry joint somewhere.......
Now my other MK111 is doing exactly the same thing !
I would be grateful if anybody has any ideas on where to look for the fault.... ( to save another trip to an auto electrician).
Regards
Will Scollay ( known these days a "chilly Willy" )
---
Supra Club of New Zealand
http://www.supras.org.nz/
---
Supra Club of New Zealand
http://www.supras.org.nz/ Get more from the Web. FREE MSN Explorer download : http://explorer.msn.com

(html version)
Reply

Re: 7m heater   2002-07-10 22:34:00 <Glen Wolfe>

A drop-in replacement? - so the resistor pack input activated from the heater
control will power an oscillator and, say, triac - different power source input
creating oscillators with differing mark-space ratios?

Or are you planning a different control input signal mechanism?

BTW I am surprised the ceramics break down (I think I used 4 x 12 R 5 w in
parallel - 20 w still air ambient rating for an anticipated load of <15w in
flowing air - but they did take a bit of shaping to the cavity ... the original
is only a filament.)

Lee Dobson wrote:

> Should have it in this weekend
>
> As marc said it uses pulsed width modulation to switch the motor on and off
> therefore you can use small currents to drive the circuit and do away with
> the large ceramic style resistors that always seem to break down
>
> Will keep all informed to its completion
>
> Cheers
> Lee
>
> ----- Original Message -----
> From: <marc.a@paradise.net.nz>
> To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
> Sent: Wednesday, July 10, 2002 9:12 AM
> Subject: [sconz] Re: 7m heater
>
> >
> > Lee D was talking about replacing this resistor pack with an electronic
> PWM
> > circuit instead; hows this going Lee?
> >
> >
> > > with a new commutator (for $A 195) but the speed failure was due to the
> > > series resistance wire breaking. Low fan speed is achieved by placing a
> > > resistance in the current path to the motor - the higher resistance
> > > (for
> > > low speed) being a coil of thin wire. Since this needs to get rid of
> > > quite a bit of heat, it is mounted on a plate which projects it into
> >
> > ---
> > Supra Club of New Zealand
> > http://www.supras.org.nz/
> >
>
> ---
> Supra Club of New Zealand
> http://www.supras.org.nz/

--
#################################################################
Dr Glen Wolfe
Software Engineer g.wolfe@computer.org
#################################################################


Reply

Re: 7m heater   2002-07-11 08:40:00 <Lee Dobson>
The output is a simple 555 timer circuit that varies the mark to space
ratio, and yes I have been using 5W ceramic resistors and have found that
they do break down. My car is a MKII and the fitting is almost drop in but
I haven't investigated fitting it to anything else.

Please note that I am not trying to modify the heater system for any other
reason than to improve its reliability as I have had problems with it and
wanted to come up with a more reliable solution

Regards
Lee Dobson

----- Original Message -----
From: Glen Wolfe <g.wolfe@computer.org>
To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
Sent: Wednesday, July 10, 2002 10:30 PM
Subject: [sconz] Re: 7m heater


>
> A drop-in replacement? - so the resistor pack input activated from the
heater
> control will power an oscillator and, say, triac - different power source
input
> creating oscillators with differing mark-space ratios?
>
> Or are you planning a different control input signal mechanism?
>
> BTW I am surprised the ceramics break down (I think I used 4 x 12 R 5 w in
> parallel - 20 w still air ambient rating for an anticipated load of <15w
in
> flowing air - but they did take a bit of shaping to the cavity ... the
original
> is only a filament.)
>
> Lee Dobson wrote:
>
> > Should have it in this weekend
> >
> > As marc said it uses pulsed width modulation to switch the motor on and
off
> > therefore you can use small currents to drive the circuit and do away
with
> > the large ceramic style resistors that always seem to break down
> >
> > Will keep all informed to its completion
> >
> > Cheers
> > Lee
> >
> > ----- Original Message -----
> > From: <marc.a@paradise.net.nz>
> > To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
> > Sent: Wednesday, July 10, 2002 9:12 AM
> > Subject: [sconz] Re: 7m heater
> >
> > >
> > > Lee D was talking about replacing this resistor pack with an
electronic
> > PWM
> > > circuit instead; hows this going Lee?
> > >
> > >
> > > > with a new commutator (for $A 195) but the speed failure was due to
the
> > > > series resistance wire breaking. Low fan speed is achieved by
placing a
> > > > resistance in the current path to the motor - the higher resistance
> > > > (for
> > > > low speed) being a coil of thin wire. Since this needs to get rid of
> > > > quite a bit of heat, it is mounted on a plate which projects it into
> > >
> > > ---
> > > Supra Club of New Zealand
> > > http://www.supras.org.nz/
> > >
> >
> > ---
> > Supra Club of New Zealand
> > http://www.supras.org.nz/
>
> --
> #################################################################
> Dr Glen Wolfe
> Software Engineer g.wolfe@computer.org
> #################################################################
>
>
>
> ---
> Supra Club of New Zealand
> http://www.supras.org.nz/


Reply

Re: 7m heater   2002-07-11 23:30:00 <Glen Wolfe>

My system does produce heat but usually small amounts and only after the engine
is warm i.e. it will maintain a comfortable temperature but doesn't hurry to get
there. If I hit the A/C switch, I will only ever get cold air, although just
detectable flow if the cabin temperature is already low. Does anyone know if
these systems were intended to be reverse cycle? (GA70)

Lee Dobson wrote:

> The output is a simple 555 timer circuit that varies the mark to space
> ratio, and yes I have been using 5W ceramic resistors and have found that
> they do break down. My car is a MKII and the fitting is almost drop in but
> I haven't investigated fitting it to anything else.
>

Sounds like a reasonably simple solution, and a compact one - how do you deal
with the varying voltage across the resistor pack - probably 3V (high speed) - 9
V (low speed). I guess adding an earth feed would give you constant 12/13V for
the control circuit. Is your resistance pack mounted in the fan / heater air
ducting?

>
> Please note that I am not trying to modify the heater system for any other
> reason than to improve its reliability as I have had problems with it and
> wanted to come up with a more reliable solution
>
> Regards
> Lee Dobson
>
> ----- Original Message -----
> From: Glen Wolfe <g.wolfe@computer.org>
> To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
> Sent: Wednesday, July 10, 2002 10:30 PM
> Subject: [sconz] Re: 7m heater
>
> >
> > A drop-in replacement? - so the resistor pack input activated from the
> heater
> > control will power an oscillator and, say, triac - different power source
> input
> > creating oscillators with differing mark-space ratios?
> >
> > Or are you planning a different control input signal mechanism?
> >
> > BTW I am surprised the ceramics break down (I think I used 4 x 12 R 5 w in
> > parallel - 20 w still air ambient rating for an anticipated load of <15w
> in
> > flowing air - but they did take a bit of shaping to the cavity ... the
> original
> > is only a filament.)
> >
> > Lee Dobson wrote:
> >
> > > Should have it in this weekend
> > >
> > > As marc said it uses pulsed width modulation to switch the motor on and
> off
> > > therefore you can use small currents to drive the circuit and do away
> with
> > > the large ceramic style resistors that always seem to break down
> > >
> > > Will keep all informed to its completion
> > >
> > > Cheers
> > > Lee
> > >
> > > ----- Original Message -----
> > > From: <marc.a@paradise.net.nz>
> > > To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
> > > Sent: Wednesday, July 10, 2002 9:12 AM
> > > Subject: [sconz] Re: 7m heater
> > >
> > > >
> > > > Lee D was talking about replacing this resistor pack with an
> electronic
> > > PWM
> > > > circuit instead; hows this going Lee?
> > > >
> > > >
> > > > > with a new commutator (for $A 195) but the speed failure was due to
> the
> > > > > series resistance wire breaking. Low fan speed is achieved by
> placing a
> > > > > resistance in the current path to the motor - the higher resistance
> > > > > (for
> > > > > low speed) being a coil of thin wire. Since this needs to get rid of
> > > > > quite a bit of heat, it is mounted on a plate which projects it into
> > > >
> > > > ---
> > > > Supra Club of New Zealand
> > > > http://www.supras.org.nz/
> > > >
> > >
> > > ---
> > > Supra Club of New Zealand
> > > http://www.supras.org.nz/
> >
> > --
> > #################################################################
> > Dr Glen Wolfe
> > Software Engineer g.wolfe@computer.org
> > #################################################################
> >
> >
> >
> > ---
> > Supra Club of New Zealand
> > http://www.supras.org.nz/
>
> ---
> Supra Club of New Zealand
> http://www.supras.org.nz/

--
#################################################################
Dr Glen Wolfe
Software Engineer g.wolfe@computer.org
#################################################################


Reply

Re: 7m heater   2002-07-12 08:59:00 <marc.a@...>
Drop in :-) Dick Smith have a 12v drill/motor controller kit which can be
easily modified to replace the Supra's fan control current limit resistors.



>
> A drop-in replacement? - so the resistor pack input activated from the
> heater
> control will power an oscillator and, say, triac - different power
> source input
> creating oscillators with differing mark-space ratios?
>
> Or are you planning a different control input signal mechanism?
>
> BTW I am surprised the ceramics break down (I think I used 4 x 12 R 5 w
> in
> parallel - 20 w still air ambient rating for an anticipated load of <15w
> in
> flowing air - but they did take a bit of shaping to the cavity ... the
> original
> is only a filament.)
Reply

Re: 7m heater   2002-07-12 09:03:00 <Lee Dobson>
the original one was but the new unit does not require cooling because the
current usage for the pwm unit is so small, so it is all mousted in a box
about the size of 2 matchboxes

Cheers
Lee
----- Original Message -----
From: Glen Wolfe <g.wolfe@computer.org>
To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
Sent: Thursday, July 11, 2002 11:26 PM
Subject: [sconz] Re: 7m heater


>
> My system does produce heat but usually small amounts and only after the
engine
> is warm i.e. it will maintain a comfortable temperature but doesn't hurry
to get
> there. If I hit the A/C switch, I will only ever get cold air, although
just
> detectable flow if the cabin temperature is already low. Does anyone know
if
> these systems were intended to be reverse cycle? (GA70)
>
> Lee Dobson wrote:
>
> > The output is a simple 555 timer circuit that varies the mark to space
> > ratio, and yes I have been using 5W ceramic resistors and have found
that
> > they do break down. My car is a MKII and the fitting is almost drop in
but
> > I haven't investigated fitting it to anything else.
> >
>
> Sounds like a reasonably simple solution, and a compact one - how do you
deal
> with the varying voltage across the resistor pack - probably 3V (high
speed) - 9
> V (low speed). I guess adding an earth feed would give you constant
12/13V for
> the control circuit. Is your resistance pack mounted in the fan / heater
air
> ducting?
>
> >
> > Please note that I am not trying to modify the heater system for any
other
> > reason than to improve its reliability as I have had problems with it
and
> > wanted to come up with a more reliable solution
> >
> > Regards
> > Lee Dobson
> >
> > ----- Original Message -----
> > From: Glen Wolfe <g.wolfe@computer.org>
> > To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
> > Sent: Wednesday, July 10, 2002 10:30 PM
> > Subject: [sconz] Re: 7m heater
> >
> > >
> > > A drop-in replacement? - so the resistor pack input activated from the
> > heater
> > > control will power an oscillator and, say, triac - different power
source
> > input
> > > creating oscillators with differing mark-space ratios?
> > >
> > > Or are you planning a different control input signal mechanism?
> > >
> > > BTW I am surprised the ceramics break down (I think I used 4 x 12 R 5
w in
> > > parallel - 20 w still air ambient rating for an anticipated load of
<15w
> > in
> > > flowing air - but they did take a bit of shaping to the cavity ... the
> > original
> > > is only a filament.)
> > >
> > > Lee Dobson wrote:
> > >
> > > > Should have it in this weekend
> > > >
> > > > As marc said it uses pulsed width modulation to switch the motor on
and
> > off
> > > > therefore you can use small currents to drive the circuit and do
away
> > with
> > > > the large ceramic style resistors that always seem to break down
> > > >
> > > > Will keep all informed to its completion
> > > >
> > > > Cheers
> > > > Lee
> > > >
> > > > ----- Original Message -----
> > > > From: <marc.a@paradise.net.nz>
> > > > To: Supra Club of NZ Mailing List <sconz@supras.org.nz>
> > > > Sent: Wednesday, July 10, 2002 9:12 AM
> > > > Subject: [sconz] Re: 7m heater
> > > >
> > > > >
> > > > > Lee D was talking about replacing this resistor pack with an
> > electronic
> > > > PWM
> > > > > circuit instead; hows this going Lee?
> > > > >
> > > > >
> > > > > > with a new commutator (for $A 195) but the speed failure was due
to
> > the
> > > > > > series resistance wire breaking. Low fan speed is achieved by
> > placing a
> > > > > > resistance in the current path to the motor - the higher
resistance
> > > > > > (for
> > > > > > low speed) being a coil of thin wire. Since this needs to get
rid of
> > > > > > quite a bit of heat, it is mounted on a plate which projects it
into
> > > > >
> > > > > ---
> > > > > Supra Club of New Zealand
> > > > > http://www.supras.org.nz/
> > > > >
> > > >
> > > > ---
> > > > Supra Club of New Zealand
> > > > http://www.supras.org.nz/
> > >
> > > --
> > > #################################################################
> > > Dr Glen Wolfe
> > > Software Engineer g.wolfe@computer.org
> > > #################################################################
> > >
> > >
> > >
> > > ---
> > > Supra Club of New Zealand
> > > http://www.supras.org.nz/
> >
> > ---
> > Supra Club of New Zealand
> > http://www.supras.org.nz/
>
> --
> #################################################################
> Dr Glen Wolfe
> Software Engineer g.wolfe@computer.org
> #################################################################
>
>
>
> ---
> Supra Club of New Zealand
> http://www.supras.org.nz/
>


Reply

Re: 7m heater   2002-07-12 09:12:00 <marc.a@...>


> the original one was but the new unit does not require cooling because
> the
> current usage for the pwm unit is so small, so it is all mousted in a
> box

Replacing the linear regulator with PWM (switchmode) regulation means much
lower current dissipation as heat - we're not relying on a big resistor to
voltage drop!

-Marc

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