Hickok 155 Traceometer

6/20/2007 6:24:40 PMplanigan

I am in the initial stages of attempting to restore this unit. The DC Volt meter is kaput but I have located a replacement. Starting at the rectifier I noted that there are 7 wires that go to the tube heaters in the RF/IF section of the unit. This opposed to the normal "daisy chaining" of the heaters. Can does anyone know or can anyone venture a guess as to why this was done? I am thinking of "daisy chaining" them to unclutter the chassis wiring.

6/20/2007 7:19:56 PMEdd

I was only thinking that if the sections WERE partitioned off with metal shielding, it might be quite troublesome to daisy chain filament wiring in its routing.....therefore they just made a direct shot to the individual sections.
I can also surmise that the supply routing to the DC voltmeter section in the schemas bottom left corner section, the dedicated audio section at right and center schema location and the osc level metering secton at left center location, all being low level and separate functions might negate any problem with their fil supply sourcing. But lastly, if you look at the RF-IF section across the top with its ultimate detection and metering at the end. There is one FIERCE cascaded gain present there, HOWEVER I see no concern in the manner of choke coil isolation or cap bypassing being incorporated in their wire routing between those tubes.
So, in the end, that is the sole area that I might suspicion any problem with .......so try your wiring, but go to that circuitry spot first if any "performance eccentricities" are experienced .

Hickok 155...........(Great shades of a Channelyst ! )

73's de Edd

-------------------------------------------------------------------------------------BT-------------------------------------------------------------------------------------------

: I am in the initial stages of attempting to restore this unit. The DC Volt meter is kaput but I have located a replacement. Starting at the rectifier I noted that there are 7 wires that go to the tube heaters in the RF/IF section of the unit. This opposed to the normal "daisy chaining" of the heaters. Can does anyone know or can anyone venture a guess as to why this was done? I am thinking of "daisy chaining" them to unclutter the chassis wiring.

6/21/2007 5:03:57 PMplanigan

Edd, thank you. At least now I have some reason to leave it as designed. Before I was thinking the amp draw was the reason. Also now the cable harnesses make sense. It was to avoid stray signals. Just as an aside, when I removed the face plate I had to remove the input jacks. On the RF/IF and AF inputs there was a wire with a spring around it. I'm thinking some type of crazy resistor but no, it a shielded cable!
PL

:I was only thinking that if the sections WERE partitioned off with metal shielding, it might be quite troublesome to daisy chain filament wiring in its routing.....therefore they just made a direct shot to the individual sections.
:I can also surmise that the supply routing to the DC voltmeter section in the schemas bottom left corner section, the dedicated audio section at right and center schema location and the osc level metering secton at left center location, all being low level and separate functions might negate any problem with their fil supply sourcing. But lastly, if you look at the RF-IF section across the top with its ultimate detection and metering at the end. There is one FIERCE cascaded gain present there, HOWEVER I see no concern in the manner of choke coil isolation or cap bypassing being incorporated in their wire routing between those tubes.
:So, in the end, that is the sole area that I might suspicion any problem with .......so try your wiring, but go to that circuitry spot first if any "performance eccentricities" are experienced .
:
:Hickok 155...........(Great shades of a Channelyst ! )
:
:73's de Edd
:
:-------------------------------------------------------------------------------------BT-------------------------------------------------------------------------------------------
:
:
:: I am in the initial stages of attempting to restore this unit. The DC Volt meter is kaput but I have located a replacement. Starting at the rectifier I noted that there are 7 wires that go to the tube heaters in the RF/IF section of the unit. This opposed to the normal "daisy chaining" of the heaters. Can does anyone know or can anyone venture a guess as to why this was done? I am thinking of "daisy chaining" them to unclutter the chassis wiring.

6/21/2007 6:51:05 PMplanigan

Another questions, on checking the power transformer I have my HV 250-250 CT, 5.6V, 6.8V and (suprise, suprise) 120V. What is the second 120V winding for? Not called for in the schematic. My thought is to cap the end of the leads. Is that advisable? If not where to I put then (lets not get carried away here)? PL

: Edd, thank you. At least now I have some reason to leave it as designed. Before I was thinking the amp draw was the reason. Also now the cable harnesses make sense. It was to avoid stray signals. Just as an aside, when I removed the face plate I had to remove the input jacks. On the RF/IF and AF inputs there was a wire with a spring around it. I'm thinking some type of crazy resistor but no, it a shielded cable!
: PL
:
:
:
:
:
::I was only thinking that if the sections WERE partitioned off with metal shielding, it might be quite troublesome to daisy chain filament wiring in its routing.....therefore they just made a direct shot to the individual sections.
::I can also surmise that the supply routing to the DC voltmeter section in the schemas bottom left corner section, the dedicated audio section at right and center schema location and the osc level metering secton at left center location, all being low level and separate functions might negate any problem with their fil supply sourcing. But lastly, if you look at the RF-IF section across the top with its ultimate detection and metering at the end. There is one FIERCE cascaded gain present there, HOWEVER I see no concern in the manner of choke coil isolation or cap bypassing being incorporated in their wire routing between those tubes.
::So, in the end, that is the sole area that I might suspicion any problem with .......so try your wiring, but go to that circuitry spot first if any "performance eccentricities" are experienced .
::
::Hickok 155...........(Great shades of a Channelyst ! )
::
::73's de Edd
::
::-------------------------------------------------------------------------------------BT-------------------------------------------------------------------------------------------
::
::
::: I am in the initial stages of attempting to restore this unit. The DC Volt meter is kaput but I have located a replacement. Starting at the rectifier I noted that there are 7 wires that go to the tube heaters in the RF/IF section of the unit. This opposed to the normal "daisy chaining" of the heaters. Can does anyone know or can anyone venture a guess as to why this was done? I am thinking of "daisy chaining" them to unclutter the chassis wiring.

6/21/2007 9:18:09 PMEdd

If you will look at the instruments manual on page 2 statement 1 " If the unit is wired for 220 volt AC operation or for 25 ~ operation" (and... of course..... solely the latter aspect would certainly require a more massive core design on its transformer)
So what I believe that you have is the additional primary winding in such manner the two primary windings could be connected series aiding such that the unit would be ready to use for European / Foreign use on 220 line voltage as was mentioned. Considering they had that foreign marketing niche in their sights in 1941 and I certainly would thought that would have, or even having been considering the use of that equipment by foreign based US companies.

Another nuance from the norm was noticed in the input attenuation schemes of the RF-IF and Osc circuitry inputs whereupon they were incorporating the Z effects of different values of caps into their input attenuator networks vice the conventional proportionally arranged fully resistive dividers.

Thirdly, back to that...... freebie, at no extra charge....... additional winding mentioned. If it was my situation I would make a further evaluation of it in the following manner :

Initially take a DVM, AC voltage reading of it unloaded and log down the voltage. Then additionally compute that voltage value at both 10% and 20% lesser values (loaded factor).
Then you would have the winding metered and then load down the winding with a 500 ohm 25 watt wirewound resistor (Or a combinational string or cluster of values to come within that ball park resistive figure.) A connection being made just long enough to take a reading is all that is needed, and in that quick sampling time, even a 10-15 watt rating would be permissible for that sole few seconds of loading. Then you can take note if whether that loading had pulled down the voltage to or below that pre-calculated 10-20 % reduction value.
The figures of 10 and 20 % are relevant to the quality and design parameters within the transformer. A good quality Mil spec, Industrial grade
of transformer typically pulls down only in the order of 10% when taxed up to its rated / specified loading level. Some current day run of the mill transformers...Radio Shack, Cal-rad, etc will have loaded down and dropped down in the order of 20 % at their "specified load rating " levels.

Soooo if that voltage read is still not encroaching upon those 10-20 % loading figures, it would be permissible to route that winding to an AC plug, such that it could feed AC power to a common AC/DC radio that you might be working on...thus providing an isolation transformer safety feature..... to chassis and the power supply of that radio.

I really think that if you keep up the loading test that you might find a 250 ohm load resistor still not be pulling down the supply to those figures, therefore, at that, the winding would have a 50 watt capability...or possibly even more.
Most common Ackey-Dackey receivers power consumptions tend to be falling within that 25-50 watt category.

73's de Edd

---------------------------------------------------------------------------------------------BT-------------------------------------------------------------------------------------------------

: Another questions, on checking the power transformer I have my HV 250-250 CT, 5.6V, 6.8V and (suprise, suprise) 120V. What is the second 120V winding for? Not called for in the schematic. My thought is to cap the end of the leads. Is that advisable? If not where to I put then (lets not get carried away here)? PL
:
:
:: Edd, thank you. At least now I have some reason to leave it as designed. Before I was thinking the amp draw was the reason. Also now the cable harnesses make sense. It was to avoid stray signals. Just as an aside, when I removed the face plate I had to remove the input jacks. On the RF/IF and AF inputs there was a wire with a spring around it. I'm thinking some type of crazy resistor but no, it a shielded cable!
:: PL
::
::
::
::
::
:::I was only thinking that if the sections WERE partitioned off with metal shielding, it might be quite troublesome to daisy chain filament wiring in its routing.....therefore they just made a direct shot to the individual sections.
:::I can also surmise that the supply routing to the DC voltmeter section in the schemas bottom left corner section, the dedicated audio section at right and center schema location and the osc level metering secton at left center location, all being low level and separate functions might negate any problem with their fil supply sourcing. But lastly, if you look at the RF-IF section across the top with its ultimate detection and metering at the end. There is one FIERCE cascaded gain present there, HOWEVER I see no concern in the manner of choke coil isolation or cap bypassing being incorporated in their wire routing between those tubes.
:::So, in the end, that is the sole area that I might suspicion any problem with .......so try your wiring, but go to that circuitry spot first if any "performance eccentricities" are experienced .
:::
:::Hickok 155...........(Great shades of a Channelyst ! )
:::
:::73's de Edd
:::
:::-------------------------------------------------------------------------------------BT-------------------------------------------------------------------------------------------
:::
:::
:::: I am in the initial stages of attempting to restore this unit. The DC Volt meter is kaput but I have located a replacement. Starting at the rectifier I noted that there are 7 wires that go to the tube heaters in the RF/IF section of the unit. This opposed to the normal "daisy chaining" of the heaters. Can does anyone know or can anyone venture a guess as to why this was done? I am thinking of "daisy chaining" them to unclutter the chassis wiring.

6/22/2007 12:23:26 PMplanigan

Edd, thank you very much. I think I will just cap the wires with small wire nuts. I don't want to add any extra load to Xfmer. This project is becoming more daunting by the minute. The components are a mixed bag, dog bone resistors and what looks like resistors in a tube, not the carbon composite type but some interim style. The battery section is completely gone, no idea how it was physically connected and resistors not schematic values. I'm hoping someone who has a unit can get me some pix's and verify that the schematic, if followed, will work. For now I am replacing the resistors/condensors on the four range switches as they are on the switches them selves and can be done out of the chassis. There is a choke that looks like OEM mounted to chassis(smaller and in addition to rectifier)which doesn't appear on schematic, at least I can't find it, that I'm worried about. All these little glitches have me wondering if I have the complete schematric or if manufacturer made modifications and never came out with revised schematic. Drawing dated 1940, but a label which has subsequently crumbled had wiring check dates 45'. After this I think I'll have to start another string with further problems that I'm sure I'll run into (Murphy's Law). PL

Agreed......... that the extra winding was not depicted on the schema, but should it be in the same voltage range of the line voltage that is put into the set...and considering that it is wound innermost, and close to the core such as the primary is, I certainly expect it to be an additional primary winding.
:
:If you will look at the instruments manual on page 2 statement 1 " If the unit is wired for 220 volt AC operation or for 25 ~ operation" (and... of course..... solely the latter aspect would certainly require a more massive core design on its transformer)
:So what I believe that you have is the additional primary winding in such manner the two primary windings could be connected series aiding such that the unit would be ready to use for European / Foreign use on 220 line voltage as was mentioned. Considering they had that foreign marketing niche in their sights in 1941 and I certainly would thought that would have, or even having been considering the use of that equipment by foreign based US companies.
:
:Another nuance from the norm was noticed in the input attenuation schemes of the RF-IF and Osc circuitry inputs whereupon they were incorporating the Z effects of different values of caps into their input attenuator networks vice the conventional proportionally arranged fully resistive dividers.
:
:Thirdly, back to that...... freebie, at no extra charge....... additional winding mentioned. If it was my situation I would make a further evaluation of it in the following manner :
:
:Initially take a DVM, AC voltage reading of it unloaded and log down the voltage. Then additionally compute that voltage value at both 10% and 20% lesser values (loaded factor).
:Then you would have the winding metered and then load down the winding with a 500 ohm 25 watt wirewound resistor (Or a combinational string or cluster of values to come within that ball park resistive figure.) A connection being made just long enough to take a reading is all that is needed, and in that quick sampling time, even a 10-15 watt rating would be permissible for that sole few seconds of loading. Then you can take note if whether that loading had pulled down the voltage to or below that pre-calculated 10-20 % reduction value.
:The figures of 10 and 20 % are relevant to the quality and design parameters within the transformer. A good quality Mil spec, Industrial grade
:of transformer typically pulls down only in the order of 10% when taxed up to its rated / specified loading level. Some current day run of the mill transformers...Radio Shack, Cal-rad, etc will have loaded down and dropped down in the order of 20 % at their "specified load rating " levels.
:
:Soooo if that voltage read is still not encroaching upon those 10-20 % loading figures, it would be permissible to route that winding to an AC plug, such that it could feed AC power to a common AC/DC radio that you might be working on...thus providing an isolation transformer safety feature..... to chassis and the power supply of that radio.
:
:I really think that if you keep up the loading test that you might find a 250 ohm load resistor still not be pulling down the supply to those figures, therefore, at that, the winding would have a 50 watt capability...or possibly even more.
:Most common Ackey-Dackey receivers power consumptions tend to be falling within that 25-50 watt category.
:
:73's de Edd
:
:---------------------------------------------------------------------------------------------BT-------------------------------------------------------------------------------------------------
:
:
:: Another questions, on checking the power transformer I have my HV 250-250 CT, 5.6V, 6.8V and (suprise, suprise) 120V. What is the second 120V winding for? Not called for in the schematic. My thought is to cap the end of the leads. Is that advisable? If not where to I put then (lets not get carried away here)? PL
::
::
::: Edd, thank you. At least now I have some reason to leave it as designed. Before I was thinking the amp draw was the reason. Also now the cable harnesses make sense. It was to avoid stray signals. Just as an aside, when I removed the face plate I had to remove the input jacks. On the RF/IF and AF inputs there was a wire with a spring around it. I'm thinking some type of crazy resistor but no, it a shielded cable!
::: PL
:::
:::
:::
:::
:::
::::I was only thinking that if the sections WERE partitioned off with metal shielding, it might be quite troublesome to daisy chain filament wiring in its routing.....therefore they just made a direct shot to the individual sections.
::::I can also surmise that the supply routing to the DC voltmeter section in the schemas bottom left corner section, the dedicated audio section at right and center schema location and the osc level metering secton at left center location, all being low level and separate functions might negate any problem with their fil supply sourcing. But lastly, if you look at the RF-IF section across the top with its ultimate detection and metering at the end. There is one FIERCE cascaded gain present there, HOWEVER I see no concern in the manner of choke coil isolation or cap bypassing being incorporated in their wire routing between those tubes.
::::So, in the end, that is the sole area that I might suspicion any problem with .......so try your wiring, but go to that circuitry spot first if any "performance eccentricities" are experienced .
::::
::::Hickok 155...........(Great shades of a Channelyst ! )
::::
::::73's de Edd
::::
::::-------------------------------------------------------------------------------------BT-------------------------------------------------------------------------------------------
::::
::::
::::: I am in the initial stages of attempting to restore this unit. The DC Volt meter is kaput but I have located a replacement. Starting at the rectifier I noted that there are 7 wires that go to the tube heaters in the RF/IF section of the unit. This opposed to the normal "daisy chaining" of the heaters. Can does anyone know or can anyone venture a guess as to why this was done? I am thinking of "daisy chaining" them to unclutter the chassis wiring.