Heathkit Service Bulletins - HD-1250 (Revised & Complete)

[Joseph W Lutz]

                        October 10, 1977
HD-1250                                         Bulletin No:
Solid State Dip Meter                           HD-1250-1

        Calibration of Oscillator Circuit & Check-Out of Detector
                        Circuit Operation

++++Information not yet available++++
------------------------------------------------------------------------------------------------------------------
                        February 27, 1981
HD-1250                                         Bulletin No:
Solid State Dip Meter                           HD-1250-2

        Low or No Meter Indication With Brown Coil Installed

++++Information not yet available++++
------------------------------------------------------------------------------------------------------------------
                        July 30, 1982
HD-1250                                         Bulletin No:
Solid State Dip Meter                           HD-1250-3

                Will Not Oscillate at High Frequency

++++Information not yet available++++
-----------------------------------------------------------------------------------------------------------------
                        January 18, 1985
HD-1250                                         Bulletin No:
Solid State Dip Meter                           HD-1250-4

                                   Oscillator Dead

On the oscillator board, check Q11 [PN 417-290] for short between
collector and transistor case.  The metal case on the #417-290
transistors should be isolated from the collector.  Defective transistors
found in Parts Replacement stock and kits in finished goods had a date
code of 413.  Heath Parts Replacement stock has been 100% checked.
Finished goods will be inserted with good #417-290 transistors.
--------------------------------------------------------------------------------------------------------------------
                        February 8, 1985
HD-1250                                         Bulletin No:
Solid State Dip Meter                           HD-1250-5

                     Unit Oscillates Without Coil Installed

The circuitry of Q21 self-oscillates when no coil is installed, causing a
full-scale deflection of the meter.  To correct this problem, install a
ferrite bead [PN 475-15] on the G1 lead of Q21.

The next production of kits will have the ferrite bead and insert [PN
591-4661].  Present stock of kits will not be inserted.
--------------------------------------------------------------------------------------------------------------------
                        July 31, 1987
HD-1250                                         Bulletin No:
Solid State Dip Meter                           HD-1250-6

                     5 pF, 500 Volt Capacitor [PN 21-157] NLA

The 5 pF, 500 volt capacitor at C13 is no longer available from our
vendors.  C13 is changed to a 5 pf, 50 volt capacitor [PN 21-7621-05].
-------------------------------------------------------------------------------------------------------------------
                        November 28, 1988
HD-1250                                         Bulletin No:
Solid State Dip Meter                           HD-1250-7

                      On/Off Pushbutton Knob Change

Purchasing can no longer buy the original pushbutton knob.  The knob is
changed:

        From a [PN 462-1047] knob to a [PN 462-1303] knob.
-------------------------------------------------------------------------------------------------------------------
Thats everything I hold up to 1989 that covers the HD-1250. Enjoy!
-------------------------------------------------------------------------------------------------------------------


73 de Joe  W7LPF/4  [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]

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