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Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
This model is a factory assembled model, and wasn't available as a kit,
AFAICT. Dual counter A-B, single 8-digit LED display (7-segment LED green or red digits). Input A 5Hz-175MHz Input B 5Hz-2MHz The Input B doesn't show a count when a signal is applied. The Input A section seems to operate as it should. I've seen that the actual circuit section for Input B does have an output signal which is connected to the main board at J103. I can also see that the counter/display IC is getting good signals at the correct pins.. input A and B, and control. Some repairs were made by previous owner, it seems, such as replacement of the original Frequency Counter/Timer display driver U20, with an ICM7226AIJL (high reliability ceramic). I first assumed that someone may have applied over-voltage(s) to the input channels, and smoked the counter/display driver IC, but I've seen random numbers displayed as I probed around the area of IC18 and the counter/driver IC, which indicates that the unit can display readings for Input B (no signal applied to Input A), but the displayed count is incorrect and inconsistent. An Intersil ICM7226A/B application/datasheet was included with the counter unit, and found to be installed in the unit. The ICM7226 is capable of 2 inputs A & B, and up to 100MHz as a multi-function (frequency/period) counter and 8 digit display driver. http://www.nostalgickitscentral.com/...hkit_test.html The the counter/driver IC, and a circuit IC U18 CD74HCT86E (quad 2-input Exclusive-OR), and possibly one other support IC may have been replaced. There was evidence of what appears to be probe-skid-type, or tool scratches on the bottom of the board in the area of the input circuitry section of Input A. The majority of the ICs are Hitachi, and a couple are Motorola and RCA devices. A third BNC input connector located on the rear panel is labeled TOTALIZE. Another aspect that I'm unsure of is one of the functions.. there is a selection of FR as one of the unit's functions, and since there is already one marked FREQ, I think FR represents something else. The other functions a PER (period) TI (time interval?) TOTAL (totalize) CHK (check display and indicators) wb_wildbill-AT-yah-oh-oh.com -- Cheers, WB .............. |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
Wild_Bill wrote in message
... This model is a factory assembled model, and wasn't available as a kit, AFAICT. Dual counter A-B, single 8-digit LED display (7-segment LED green or red digits). Input A 5Hz-175MHz Input B 5Hz-2MHz The Input B doesn't show a count when a signal is applied. The Input A section seems to operate as it should. I've seen that the actual circuit section for Input B does have an output signal which is connected to the main board at J103. I can also see that the counter/display IC is getting good signals at the correct pins.. input A and B, and control. Some repairs were made by previous owner, it seems, such as replacement of the original Frequency Counter/Timer display driver U20, with an ICM7226AIJL (high reliability ceramic). I first assumed that someone may have applied over-voltage(s) to the input channels, and smoked the counter/display driver IC, but I've seen random numbers displayed as I probed around the area of IC18 and the counter/driver IC, which indicates that the unit can display readings for Input B (no signal applied to Input A), but the displayed count is incorrect and inconsistent. An Intersil ICM7226A/B application/datasheet was included with the counter unit, and found to be installed in the unit. The ICM7226 is capable of 2 inputs A & B, and up to 100MHz as a multi-function (frequency/period) counter and 8 digit display driver. http://www.nostalgickitscentral.com/...hkit_test.html The the counter/driver IC, and a circuit IC U18 CD74HCT86E (quad 2-input Exclusive-OR), and possibly one other support IC may have been replaced. There was evidence of what appears to be probe-skid-type, or tool scratches on the bottom of the board in the area of the input circuitry section of Input A. The majority of the ICs are Hitachi, and a couple are Motorola and RCA devices. A third BNC input connector located on the rear panel is labeled TOTALIZE. Another aspect that I'm unsure of is one of the functions.. there is a selection of FR as one of the unit's functions, and since there is already one marked FREQ, I think FR represents something else. The other functions a PER (period) TI (time interval?) TOTAL (totalize) CHK (check display and indicators) wb_wildbill-AT-yah-oh-oh.com -- Cheers, WB ............. FR = Frequency Ratio ? My guess , corroded switch contacts |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
Wild_Bill wrote:
This model is a factory assembled model, and wasn't available as a kit, AFAICT. Dual counter A-B, single 8-digit LED display (7-segment LED green or red digits). Input A 5Hz-175MHz Input B 5Hz-2MHz The Input B doesn't show a count when a signal is applied. The Input A section seems to operate as it should. I've seen that the actual circuit section for Input B does have an output signal which is connected to the main board at J103. I can also see that the counter/display IC is getting good signals at the correct pins.. input A and B, and control. Some repairs were made by previous owner, it seems, such as replacement of the original Frequency Counter/Timer display driver U20, with an ICM7226AIJL (high reliability ceramic). I first assumed that someone may have applied over-voltage(s) to the input channels, and smoked the counter/display driver IC, but I've seen random numbers displayed as I probed around the area of IC18 and the counter/driver IC, which indicates that the unit can display readings for Input B (no signal applied to Input A), but the displayed count is incorrect and inconsistent. An Intersil ICM7226A/B application/datasheet was included with the counter unit, and found to be installed in the unit. The ICM7226 is capable of 2 inputs A & B, and up to 100MHz as a multi-function (frequency/period) counter and 8 digit display driver. http://www.nostalgickitscentral.com/...hkit_test.html The the counter/driver IC, and a circuit IC U18 CD74HCT86E (quad 2-input Exclusive-OR), and possibly one other support IC may have been replaced. There was evidence of what appears to be probe-skid-type, or tool scratches on the bottom of the board in the area of the input circuitry section of Input A. The majority of the ICs are Hitachi, and a couple are Motorola and RCA devices. A third BNC input connector located on the rear panel is labeled TOTALIZE. Another aspect that I'm unsure of is one of the functions.. there is a selection of FR as one of the unit's functions, and since there is already one marked FREQ, I think FR represents something else. The other functions a PER (period) TI (time interval?) TOTAL (totalize) CHK (check display and indicators) wb_wildbill-AT-yah-oh-oh.com Do you have a copy of the schematic that you can post somewhere on the web so we can take a look at the circuitry? Otherwise, it's just a shot in the dark. -- David dgminala at mediacombb dot net |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
On Jan 1, 8:01*am, "Wild_Bill" wrote:
This model is a factory assembled model, and wasn't available as a kit, AFAICT. Dual counter A-B, single 8-digit LED display (7-segment LED green or red digits). Input A 5Hz-175MHz Input B 5Hz-2MHz The Input B doesn't show a count when a signal is applied. The Input A section seems to operate as it should. I've seen that the actual circuit section for Input B does have an output signal which is connected to the main board at J103. I can also see that the counter/display IC is getting good signals at the correct pins.. input A and B, and control. Some repairs were made by previous owner, it seems, such as replacement of the original Frequency Counter/Timer display driver U20, with an ICM7226AIJL (high reliability ceramic). I first assumed that someone may have applied over-voltage(s) to the input channels, and smoked the counter/display driver IC, but I've seen random numbers displayed as I probed around the area of IC18 and the counter/driver IC, which indicates that the unit can display readings for Input B (no signal applied to Input A), but the displayed count is incorrect and inconsistent. An Intersil ICM7226A/B application/datasheet was included with the counter unit, and found to be installed in the unit. The ICM7226 is capable of 2 inputs A & B, and up to 100MHz as a multi-function (frequency/period) counter and 8 digit display driver. http://www.nostalgickitscentral.com/...hkit_test.html The the counter/driver IC, and a circuit IC U18 CD74HCT86E (quad 2-input Exclusive-OR), and possibly one other support IC may have been replaced. There was evidence of what appears to be probe-skid-type, or tool scratches on the bottom of the board in the area of the input circuitry section of Input A. The majority of the ICs are Hitachi, and a couple are Motorola and RCA devices. A third BNC input connector located on the rear panel is labeled TOTALIZE.. Another aspect that I'm unsure of is one of the functions.. there is a selection of FR as one of the unit's functions, and since there is already one marked FREQ, I think FR represents something else. The other functions a PER (period) TI (time interval?) TOTAL (totalize) CHK (check display and indicators) wb_wildbill-AT-yah-oh-oh.com -- Cheers, WB ............. My incination would be to closely examine the soldering, both rework and original. If that looks good, then apply the same signal of about 1 kHz sine to both inputs and compare the signal at the A and B input pins on the counter chip with a good 'scope. Vary the input level and see that the processed signals remain identical. If the signals are identical, then the two input channels are probably okay and the problem lies in the the control circuitry or the counter chip. Since you see operation when probing, that suggested the counter chip is good, but thre is a fault in it's control due to some sort of poor connection such as solder, a dirty switch as N. Cook suggests, or even 'lead rot' on one or more DIP packages. Neil S. |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
Thank you Nigel.. frequency ratio would likely be a function of a universal
counter with 2 inputs. There is no selector switch to select between Input A and Input B, which I think is what you were suggesting. That may seem odd (to me too).. that's where a manual would be handy, to see what the actual operating procedures are like. I forgot to mench, something that you generally include, which would be the age of the instrument.. probably from about 1988. -- Cheers, WB .............. "N_Cook" wrote in message ... FR = Frequency Ratio ? My guess , corroded switch contacts |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
I appreciate your offer to assist, David, but nothing came with the unit,
other than the Intersil ICM7226 counter/driver datasheet. -- Cheers, WB .............. "Dave M" wrote in message ... Do you have a copy of the schematic that you can post somewhere on the web so we can take a look at the circuitry? Otherwise, it's just a shot in the dark. -- David dgminala at mediacombb dot net |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
Wild_Bill wrote:
This model is a factory assembled model, and wasn't available as a kit, AFAICT. Dual counter A-B, single 8-digit LED display (7-segment LED green or red digits). Input A 5Hz-175MHz Input B 5Hz-2MHz The Input B doesn't show a count when a signal is applied. The Input A section seems to operate as it should. ... These folks claim to have a copy for sale @ $22USD (not bad if original): http://www.vintagemanuals.com/manual...model=ETI-7040 However these folks don't have a download schematic (pity) although they do have a lot of older Heathkit info: http://www.vintage-radio.info/heathkit/ John :-#)# -- (Please post followups or tech enquiries to the newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
Thanks Neil.. my suspicion is as you suggested, as I've seen waveforms
present at the 2 inputs of the counter IC with signal generator inputs at Input A & B, and that perhaps one of a couple of other ICs may be the culprit. In numerical order, just before the ICM7226 counter IC there a U18 quad 2-input Exclusive-OR U19 HD74LS74AP dual D-type positive edge triggered F-flops with reset and clear Of course, there are numerous other signals to the counter IC that are essential for proper operation, where I believe a schematic would be most helpful. There is a Test Point pin TP1 beside U18, for example. The only obvious non-factory soldering is around the input area of the Input A circuit components, where it appears that some resistor leads were lifted to check their values. The soldering under the sockets for the 2 newer ICs (U18 and counter IC U20) looks identical to the rest of the wave-soldered factory assembly connections, although oddly enough those 2 ICs are the only ones with sockets. FWIW, I wouldn't claim that it's not possible for me to be fooled, but I've seen a lot of soldering and hand soldering generally always has certain characteristics that differ from factory connections, such as inconsistent amounts of solder applied to some pads and several other traits. -- Cheers, WB .............. "nesesu" wrote in message ... My incination would be to closely examine the soldering, both rework and original. If that looks good, then apply the same signal of about 1 kHz sine to both inputs and compare the signal at the A and B input pins on the counter chip with a good 'scope. Vary the input level and see that the processed signals remain identical. If the signals are identical, then the two input channels are probably okay and the problem lies in the the control circuitry or the counter chip. Since you see operation when probing, that suggested the counter chip is good, but thre is a fault in it's control due to some sort of poor connection such as solder, a dirty switch as N. Cook suggests, or even 'lead rot' on one or more DIP packages. Neil S. |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
On Jan 1, 4:38*pm, "Wild_Bill" wrote:
Thanks Neil.. my suspicion is as you suggested, as I've seen waveforms present at the 2 inputs of the counter IC with signal generator inputs at Input A & *B, and that perhaps one of a couple of other ICs may be the culprit. In numerical order, just before the ICM7226 counter IC there a U18 quad 2-input Exclusive-OR U19 HD74LS74AP dual D-type positive edge triggered F-flops with reset and clear Of course, there are numerous other signals to the counter IC that are essential for proper operation, where I believe a schematic would be most helpful. There is a Test Point pin TP1 beside U18, for example. The only obvious non-factory soldering is around the input area of the Input A circuit components, where it appears that some resistor leads were lifted to check their values. The soldering under the sockets for the 2 newer ICs (U18 and counter IC U20) looks identical to the rest of the wave-soldered factory assembly connections, although oddly enough those 2 ICs are the only ones with sockets. FWIW, I wouldn't claim that it's not possible for me to be fooled, but I've seen a lot of soldering and hand soldering generally always has certain characteristics that differ from factory connections, such as inconsistent amounts of solder applied to some pads and several other traits. -- Cheers, WB ............. "nesesu" wrote in message ... My incination would be to closely examine the soldering, both rework and original. If that looks good, then apply the same signal of about 1 kHz sine to both inputs and compare the signal at the A and B input pins on the counter chip with a good 'scope. Vary the input level and see that the processed signals remain identical. If the signals are identical, then the two input channels are probably okay and the problem lies in the the control circuitry or the counter chip. Since you see operation when probing, that suggested the counter chip is good, but thre is a fault in it's control due to some sort of poor connection such as solder, a dirty switch as N. Cook suggests, or even 'lead rot' on one or more DIP packages. Neil S. This data sheet looks like it gives enough information to trace through the operating parameters of the chip in your application. Heath was known to utilize the 'typical application' circuits of the manufacturers, so I would not be surprised to find the data sheet fairly close to the circuit you have. This also explains the various functions of the controls. http://www.electroniccircuits.gr/files/ICM7226.pdf Neil S. |
Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
Thanks again, Neil. You're correct that the datasheet shows all the details
of the operation of the counter/display IC.. and going thru the complete set of I/O signals will likely show if the IC is functional. I'd still like to have a manual and schematic to see what the recommended uses or limitations of the counter are, and to confirm that the correct parts are present. BTW, the unit was factory built, manufactured in Japan, so the so the design and features could be nearly identical or similar to counters of other brand names. The 80s were around the time when a lot of U.S. domestic test equipment manufacturers started selling imported models.. Leader, BK Precision etc. Browsing catalogs back then, it was common to see numerous brand models that were nearly identical except for cosmetic differences.. front panel, knob styles etc. -- Cheers, WB .............. "nesesu" wrote in message ... This data sheet looks like it gives enough information to trace through the operating parameters of the chip in your application. Heath was known to utilize the 'typical application' circuits of the manufacturers, so I would not be surprised to find the data sheet fairly close to the circuit you have. This also explains the various functions of the controls. http://www.electroniccircuits.gr/files/ICM7226.pdf Neil S. |
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